Iah Bulu does have that one weird settlement that seems to spawn far more Smear Campaigns than anywhere else, I keep hoping there is another somewhere doing the same for Settlement Defence Plans, but no luck so farI swear that the controlling Anarchy Faction there is affecting the loot table in such a way that all the good stuff spawns frequently there, because I've never seen something like this outside of Iah Bulu in the hundreds of other Settlement assaults I've conducted recently on Threat Level 3 Settlements:
At the moment the best places for Restore Missions (which are not missing https://forums.frontier.co.uk/threads/no-support-missions-are-not-missing.590553/) are probably Ti Wanjang and Sheela Na Gig, though obviously that may change on the next tick. (And may not be true now, though my script tends to have a good hit rate.)
True, they have their uses (as do Tourist sites, but more for Health Monitors than anything the OP is after). Most of the agri stuff overlaps with EXT/High Tech/IND though, so unless you're doing the genetics unlocks (or after Push in an Anarchy) I don't find them as useful as they tend to stock a lot of the useless stuff. Plus the massive one takes forever to walk acrossThe large Agri Settlements are the ones that seemingly print the most Manufacturing Instructions for me, among heaps of Production Schedules / Reports, Chemical, Genetic and occasionally Biometric and Spectral Analysis Data. I even found some Mining Analytics at one today.