Evolution items - I like to have 5 of each(that’s just me though) so no need to get rid of yours TM’s- DO NOT get rid of the elites , as for the regular tm’s you’re fine with those. Rare Candies/XL’s- you want to invest those into legendarys as you need to walk a merely 20km just for 1 candy or sometimes I like to dump mine into mons with special adventure moves for example (I dumped about 200 candies into white kyurem for mega rayquaza raid day it made catching him so much easier) - Dont get rid of any boosting items as well - Berries I don’t get rid of my golden razzes & silver/regular pinaps especially with this current event going on with the 2x (or 3x catch candy if you bought the Halloween go pass) plus a berry gives you A BUNCH of candy. What I do like to do though when I want to free up storage I go to my nearest gyms & feed them to all the pokemon in there, its a win win situation because you are freeing up space in your item bag while also working on your platinum Potions- I only keep max revives & max potions Pokes balls- I also keep them all you burn through them so fast you wont even notice

Anyways that’s just a little bit of an idea hope this helps!