Previously: seasons 1, 2, 3, 4, 5, 6, 7,8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 (plus How large are squadrons?)
On each graph, points are on the Y-axis, and squadron position on the leaderboard is on the X-axis. Both scales are logarithmic. The light grey line (diamond marker) is the numbers for the previous season, the dark grey line (triangle marker) is the numbers for the same season last year (season 14), and all stats are PC only. As in previous seasons, the approximate power-law distribution continues, allowing estimates of total activity to be made without spending too long reading the boards.
(Political is excluded, because there are well-known exploits to allow very high scores, and because it's not clear even without the exploits what it's supposed to be measuring: the in-game description of "large and happy faction" is clearly wrong - possibly this will change if they ever implement BGS happiness properly)
Anti Xeno (269 pages)
Winners: Marauder's Vanguard with ~10% of all points. Plague and The Wing of Destiny take the other trophies.
The same three names in the same order as last season. Overall activity is somewhat up, mainly driven by higher AX activity outside the top-10 squadrons.
Combat (2613 pages)
Winners: Stellanebula Project with ~1% of all points. Lavigny's Legion and AXI take the other trophies.
Not much change in combat either, with AXI coming in for the Bronze trophy instead. Overall activity is somewhat down, to its lowest level since the combat payout rebalance (though still well ahead of any pre-rebalance season).
CQC (74 pages)
Winners: We Rock You Roll with ~26% of all points. CQC Discord and Dark Enterprise take the other places.
CQC slumps to another record low, mainly from much lower scores in the top 20-30 places. Season 16 last year was the last full Horizons season and the effect of the instancing split is really clear. As a result, with over 26% of the estimated total points, WRYR had a very easy win this season and set the all-time record for "fraction of total activity by a single squadron".
Exploration (2868 pages)
Winners: United German Commanders with ~3% of all points, Intergalactic Astronomical Union and Renamed Dragons take the other trophies.
Some new names in Gold and Bronze on the exploration leaderboard. Overall activity is very similar to last season, though outside the top 10 a bit down on last year. The number of pages appears to have returned to a slowly rising trend now, but only about 20 pages a season compared with the pre-Odyssey 100+ pages. Perhaps everyone who wants a squadron now has one?
Powerplay (81 pages)
Winners: Lavigny's Legion with ~10% of all points. Aisling Wing Command and Madmen of the Mogonjo take the other trophies.
Unlike the other boards, Powerplay takes a substantial increase this season and compared with last year - no sign of post-Odyssey reductions here - for its third busiest season. For the first time ever, Federal Liberal Command are out of the top 3, bringing an end to their 22-season trophy set. There are now no squadrons to have won a trophy in every season.
Trade (2422 pages)
Winners: Winged Hussars with ~1% of all points. Threshhold and Pilots Booze Network Squadron take the other trophies.
Another trade win for the Winged Hussars, as trade activity drops off substantially this season - falling to its lowest level since Season 5.
Other comments
So, last season I noticed something a bit odd with the number of pages displayed, and this season I kept a closer eye on it.
The leaderboards behave pretty normally within a season - the number of points required for a top X place goes up fairly linearly over time for both AX (which can be stockpiled) and Combat (which can't). The number of participating squadrons gradually rises (and never, within the sampling frequency I did, ever falls!) And, within the top 100 places (on a largish leaderboard like AX or Combat, anyway) they stay on that trend after the season ends too.
But the top 1000th place behaves differently - it rises at a fairly linear rate throughout the season (at least on boards like Combat where it's present from the start), but then jumps suddenly about 50% at the end of the season. This jump also affects displayed placings: my squadron fell from 1120th on trade a week before season end, to 2440th.
Having collected more data, I'm still no clearer on what is actually happening: it seems that around 2/3 of squadrons on a mainstream activity and a substantial number on the others just don't show up on the leaderboards during the season (and this includes in-season calculations of squadron rank). At the end of the season they reappear. For some reason this seems to have minimal if any effect on top-100 squadrons, but is definitely noticeable by top-1000.
So, it's a bug. It's an unreportable bug and therefore isn't going to be fixed. But it doesn't seem to be leading to any inconsistencies in the "last season" data which is displayed - if it's wrong, it's at least consistently wrong - so I'll just keep using that for comparisons.

On each graph, points are on the Y-axis, and squadron position on the leaderboard is on the X-axis. Both scales are logarithmic. The light grey line (diamond marker) is the numbers for the previous season, the dark grey line (triangle marker) is the numbers for the same season last year (season 14), and all stats are PC only. As in previous seasons, the approximate power-law distribution continues, allowing estimates of total activity to be made without spending too long reading the boards.
(Political is excluded, because there are well-known exploits to allow very high scores, and because it's not clear even without the exploits what it's supposed to be measuring: the in-game description of "large and happy faction" is clearly wrong - possibly this will change if they ever implement BGS happiness properly)
Anti Xeno (269 pages)
Winners: Marauder's Vanguard with ~10% of all points. Plague and The Wing of Destiny take the other trophies.
The same three names in the same order as last season. Overall activity is somewhat up, mainly driven by higher AX activity outside the top-10 squadrons.
Combat (2613 pages)
Winners: Stellanebula Project with ~1% of all points. Lavigny's Legion and AXI take the other trophies.
Not much change in combat either, with AXI coming in for the Bronze trophy instead. Overall activity is somewhat down, to its lowest level since the combat payout rebalance (though still well ahead of any pre-rebalance season).
CQC (74 pages)
Winners: We Rock You Roll with ~26% of all points. CQC Discord and Dark Enterprise take the other places.
CQC slumps to another record low, mainly from much lower scores in the top 20-30 places. Season 16 last year was the last full Horizons season and the effect of the instancing split is really clear. As a result, with over 26% of the estimated total points, WRYR had a very easy win this season and set the all-time record for "fraction of total activity by a single squadron".
Exploration (2868 pages)
Winners: United German Commanders with ~3% of all points, Intergalactic Astronomical Union and Renamed Dragons take the other trophies.
Some new names in Gold and Bronze on the exploration leaderboard. Overall activity is very similar to last season, though outside the top 10 a bit down on last year. The number of pages appears to have returned to a slowly rising trend now, but only about 20 pages a season compared with the pre-Odyssey 100+ pages. Perhaps everyone who wants a squadron now has one?
Powerplay (81 pages)
Winners: Lavigny's Legion with ~10% of all points. Aisling Wing Command and Madmen of the Mogonjo take the other trophies.
Unlike the other boards, Powerplay takes a substantial increase this season and compared with last year - no sign of post-Odyssey reductions here - for its third busiest season. For the first time ever, Federal Liberal Command are out of the top 3, bringing an end to their 22-season trophy set. There are now no squadrons to have won a trophy in every season.
Trade (2422 pages)
Winners: Winged Hussars with ~1% of all points. Threshhold and Pilots Booze Network Squadron take the other trophies.
Another trade win for the Winged Hussars, as trade activity drops off substantially this season - falling to its lowest level since Season 5.
Other comments
So, last season I noticed something a bit odd with the number of pages displayed, and this season I kept a closer eye on it.
The leaderboards behave pretty normally within a season - the number of points required for a top X place goes up fairly linearly over time for both AX (which can be stockpiled) and Combat (which can't). The number of participating squadrons gradually rises (and never, within the sampling frequency I did, ever falls!) And, within the top 100 places (on a largish leaderboard like AX or Combat, anyway) they stay on that trend after the season ends too.
But the top 1000th place behaves differently - it rises at a fairly linear rate throughout the season (at least on boards like Combat where it's present from the start), but then jumps suddenly about 50% at the end of the season. This jump also affects displayed placings: my squadron fell from 1120th on trade a week before season end, to 2440th.
Having collected more data, I'm still no clearer on what is actually happening: it seems that around 2/3 of squadrons on a mainstream activity and a substantial number on the others just don't show up on the leaderboards during the season (and this includes in-season calculations of squadron rank). At the end of the season they reappear. For some reason this seems to have minimal if any effect on top-100 squadrons, but is definitely noticeable by top-1000.
So, it's a bug. It's an unreportable bug and therefore isn't going to be fixed. But it doesn't seem to be leading to any inconsistencies in the "last season" data which is displayed - if it's wrong, it's at least consistently wrong - so I'll just keep using that for comparisons.