Gen 3:
Treekco thru sceptile: I think they look my like guys, I’d like them for me.
Torchic thru blaziken: You. Strong fire type, torchic is a chick and you are a chick so there’s that too.
Mudkip thru swampert.  Me. The evolutions get progressively fatter, like me.
Zizagoon: Me. I have a little goon.
Linoone: You. Extreme speed, looks girly.
Wurmple: Me.  It looks like my lil thing
Silcoon and Cascoon: Me. Pretty useless, can learn harden.
Ralts: Me. Kind of derpy.  Not very powerful.
Kirlia and Gardevoir:  You, they are girly.
Shroomish and breloom: Me, one is just a weird plant with a face and the other is a weird mushroom thing but pretty (pretty like you) good.
Seedot: Me, it has small qualities and round qualities.
Nuzleaf and shiftry: Those can be you since you fit the bill of a dark type, and you can use leech seed on me.
Tailow and swallow: You. I think they fit you better because they are kind of graceful, fast speed, swallow is actually okay this gen.
Skitty and delcatty: You, no explanation needed.
All the ludicolo stuff:  Me, Ludicolo is fat, kind of derpy, it just fits me well.
Nosepass: Me, I’m sure your nose looks good but mine is kind of large and crooked.
Nincada: Me, it is a roach like bug.
Ninjask: You, it is very fast, can do dances, and can troll really well.
Shedinja:  Me, If you are ninjask I am shedinja.  I basically gave all my hp to you, you own me.
Mawile: You, it is a cute girl should can show two sides to her personality
Sabyleye: Me, no weaknesses except to fairies like you.  With you as mawile you are the perfect counter to me.  Well, not if will o wisp, but im dumb and not going to use that.
Gulpin and Swalot: Me. They are piles of sludge, that fits me better.
Electrike and Manectric: They are fast, could attract things, send a current through me as punishment, fits you.
Plusle and Minun: You said you hated them, so idk who they are.  The girl one is you and the boy one I me, but maybe they are just neither.
Solrock: You are solrock because the sun is hot like you.
Lunatone: I’m Lunatone because I guess I orbit around you and can’t escape.  I mean its technically I orbit around something that orbits around you but that part isn’t important.
Tropius: Me. I seem more like a tropius, Idk if I’d ever have bananas dangling from by chin, but in general this pokemon seems to have some weird qualities that fit me being weird.
Castform: You. It can use a variety of situations to its advantage, is cute, transforms in a way.
Spinda:  Me? Spinda could go either way.  It has a dumb look on its face though so that probably leans toward me.
Seviper: Me. It’s a snake.
Zangoose: You, you are the one trying to wrestle with the snake, get it under your complete control.
Volbeat: Me. No explanation needed.  Tail glow is kind of funny, Idk what you could do to make it glow, but there are ideas with that.
Illumise: You. No explanation needed.
Meditate and Medicham: You. They are kind of cute, Medicham is agile and athletic, you are a mind read.  It all fits well.
Poocheyena and Mightyena: Me.  I know you fit dark types well, but I fit being a dog somewhat.  And these aren’t that cute.
Bagon thru Salamence:  You. They are powerful mons that can intimidate, which doesn’t fit me, but they also don’t look like girls.  Still, I’ll go with personality over looks because its more important.
Beldum thru Metagross: This is similar to the problem with the salamence evo chain.  I’m not psychic, nor am I strong, but I don’t think you look like a metagross. Still, I’l go with it.
Spheal thru Walrein: Me.  They have thick fat as ability and are depicted as being a fat walrus.  That is perfect for me.
Snorunt: You.  Snorunt is kind of cute, I like the face on it, I think it fits you well.
Glalie: Me.  Glalie looks ugly but doesn’t have the stats to back it up.  That fits me.
Clampearl: You. You are like a clam and I am trying to coax the pearl out of the shell by doing everything the clam wants.  You are more attractive than a clam though.
Gorbyess: You. Can set up quickly, so good her purpose was banned.  Also, has curves in the right places.  You are like a gorbyess.
Huntail: Me. It is an ugly angler fish with no good utility.  Definitely got the wrong end of the stick like me being a boy.
Wailmer and Wailord: Me. They are whales.  You are no whale, I am.  You like being crushed sometimes though.
Numel: You.  It  is a cute fire type.  You are cute and hot.
Camerupt: Me. Its evo is kind of ugly and eruption is a move I will hopefully use again someday.
Torkoal: Me. I know it’s a fire type, but it’s a turtle that likes to blow off steam.  I get scared sometimes, so I turtle in my shell and blow off steam.
Luvdisc: Me. You hate it, so it can’t be you.  And I wuv you I guess enough to take the bullet on this one.
Jirachi: You.  It is kind of the next best thing to mew.  You have serene grace, and can definitely use a lot of the moves in its movepool on me and get me to flinch.
Deoxys: You.  You have better genetic material to pass on than me.
Kyogre: The rain is actually my tears from the ways you can make me cry.  You can summon rain that way.
Groudon: You.  I could never be something this powerful.  You bring sunshine to my life, a ray of hope.
Rayquaza: You. It flies, is very powerful, and can basically do whatever it wants.
Slakoth and slaking: Me, I am fat and lazy
Vigorith: You.  you are fit, don’t weigh much, and can be ferocious if you want to be.
Carnivia and sharpedo: You.  I know they are kind of ugly, but you can be the shark and I can be the prey.  Dark type fits you better.