Where can I find a certain Pokemon/item/move?

                
Pokemon:
https://forums.pokemmo.eu/index.php?/topic/51560-pokemmo-guide-implemented-pokemon-locations-held-items/ for single encounters Kanto/Hoenn
https://forums.pokemmo.eu/index.php?/topic/76530-pokemmo-locations-2019/ for Unova
https://forums.pokemmo.eu/index.php?/topic/94253-horde-guide-2019/ for hordes
Also Zorua in Lostlorn, in hordes, disguised as other mons (added after the creation of these guides). Use a weak AoE to break the illusion or just watch the moves.
Items:
https://forums.pokemmo.eu/index.php?/topic/76837-pokemmo-item-dex-2019/ (Outdated, some items got added since, but this is the best we have. Maybe you can create a better one?)
https://forums.pokemmo.eu/index.php?/topic/76529-storyline-guide-kanto-hoenn-sinnoh-unova-complete-walkthrough-all-items-hidden-items/
https://forums.pokemmo.eu/index.php?/topic/77124-pokemart-item-locations/
Moves:
https://forums.pokemmo.eu/index.php?/topic/106577-finding-every-move-2nd-edition/ for tutor/TM moves
https://forums.pokemmo.eu/index.php?/topic/75521-move-re-learner-guide/ for levelup moves
"Special" moves can be bought for BP in the Trainer Tower/Battle Frontier/Battle Subway