I wrote an article for offensive AP necessities. Keep in mind these are for budget/beginner teams, so what’s the best abilities for those 95+ teams won’t always be the case now because of AP constraints for the budget teams.
DBs (CBs, FS, SS) - Pick Artist. I run pick artists on all my DBs, and a lot of people do. This helps you get interceptions and increases your chance of catching deflected balls. Most higher-end DBs get pick artist for free, but there’s still a lot of DBs that can get it for 1 AP.
LBs (Users) - Lurker. If you have LBs in coverage, the lurker is an absolute must. EA has coded LBs to where they won’t animate like DBs without lurker. That’s why many people choose to use safeties at subLB instead of LBs. However, lurker lets LBs animate like DBs again, making them relevant again. Many LBs can get lurker for 1 AP, and recent LBs have started getting it for 0 AP.
DL - Inside Stuff. This is one of the best, if not the best run-stopping ability in the game. Secure Protector and Post-Up will negate Inside Stuff, which is why you’ll want to run multiple Inside Stuffs if you can afford it.
Other great defensive abilities would include Goalline Stuff (Faster blockshed on all run plays within 5 yards of the endzone), KOs (Zone is better to run with a budget team, so consider Flat Zone KO for slot/underneath guys, Deep Out Zone KO for deep guys, and Mid Zone KO for your middle of the field guys), Tackle Supreme/Secure Tackler (Higher tackle chance in conservative tackles (this ability is great when it comes to tackling the AKA HBs with Freight Train on)) and Edge Threat/Edge Threat Elite (Fast blockshed when rushing off the edges (Only use if you can get it for a discount, as most people have at least Edge Protector which negates Edge Threat)).
Like the offensive AP Necessities, comment if you think I forgot any abilities that are absolute necessities.