Disclaimer:

Many of these sprites are credited to bloodless, but at the time of writing, most of them are part of a larger GSC spriting initiative managed by bloodless, so all sprites credited to him are part of said initiative and not necessarily made by bloodless

Abomasnow front: bloodless
Abomasnow back: COMBOY
Absol back: COMBOY
Aggron front: bloodless
Aggron back: Koolboyman
Aromatisse back: SirWhibbles
Aron front: bloodless
Aron back: Koolboyman
Aurora front: SirWhibbles
Aurora back: SirWhibbles
Aurorus front: SirWhibbles
Aurorus back: SirWhibbles
Avalugg back: SirWhibbles

Beartic back: COMBOY
Bergmite front: Dragonball253
Bergmite back: SirWhibbles
Bibarel front: bloodless
Bibarel back: bloodless
Bidoof front: bloodless
Bidoof back: bloodless
Boldore front: Chris2Balls
Boldore back: COMBOY
Braixen front: Zorgoth120 / Solo993
Breloom front: bloodless
Breloom back: Koolboyman
Bronzong front: Chaos Rush
Bronzong back: Chaos Rush
Bronzor front: Chaos Rush
Bronzor back: Chaos Rush
Buizel front: bloodless
Buizel back: bloodless
Bunnelby front: SirWhibbles
Bunnelby back: SirWhibbles

Camerupt front: COMBOY
Camerupt back: COMBOY
Carbink back: SirWhibbles
Charjabug front: bloodless
Charjabug back: leparagon, devamped by Bummer
Corphish front: bloodless
Corphish back: bloodless
Cottonee front: bloodless
Cottonee back: COMBOY
Crabominable front: leparagon, devamped by Bummer
Crabominable back: PokéCommunity's Gen VII: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer
Crabrawler front: original sprite by leparagon, devamped by Bummer
Crabrawler back: original sprite by leparagon, devamped by Bummer
Crawdaunt front: bloodless
Crawdaunt back: bloodless
Croagunk front: bloodless
Croagunk back: bloodless
Crustle front: bloodless
Crustle back: COMBOY
Cubchoo front: COMBOY
Cubchoo back: COMBOY
Cutiefly front: SupahSanti
Cutiefly back: leparagon, devamped by Bummer

Deerling back: COMBOY
Deino back: COMBOY
Delphox front: Solo993
Dewott front: bloodless
Dewott back: COMBOY
Dhelmise front (bottom part): lakeofdance
Dhelmise back: leparagon, devamped by Bummer
Diggersby back: PokéCommunity's Gen VI: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer
Diancie front: SirWhibbles
Diancie back: SirWhibbles
Dragalgae front: ???
Dragalgae back: Chamber
Drampa front: SupahSanti
Drampa back: leparagon, devamped by Bummer
Drifblim front: bloodless
Drifblim back: bloodless
Drifloon front: bloodless
Drifloon back: bloodless
Drilbur back: COMBOY
Druddigon front: gmerc
Dwebble front: bloodless
Dwebble back: COMBOY

Eelektrik back: COMBOY
Eelektross back: COMBOY
Electivire front: amvz08
Electivire back: Chaos Rush
Electrike front: bloodless
Elektrike back: bloodless
Excadrill back: COMBOY

Fennekin front: SirWhibbles
Fennekin back: SirWhibbles
Flabébé front: XY Sprite Proj.
Flabébé back: XY Sprite Proj.
Floatzel front: bloodless
Floatzel back: bloodless
Floette front: PiaCarrot
Floette back: PiaCarrot
Froslass front: bloodless
Froslass back: BynineB

Gallade front: bloodless
Gallade back: Koolboyman
Gardevoir front:
Gardevoir back: Koolboyman
Gastrodon front: bloodless
Gastrodon back: bloodless
Gigalith back: lakeofdance
Glalie front: bloodless
Glalie back: Koolboyman
Gogoat front: Dragonball253
Golbat front: PiaCarrot
Grotle front: bloodless
Grotle back: bloodless
Grubbin front: SupahSanti
Grubbin back: leparagon, devamped by Bummer
Gulpin front: bloodless
Gulpin back: bloodless
Gurdurr front: Nicktendo DS

Honchkrow front: bloodless
Honchkrow back: bloodless
Honedge front: SirWhibbles
Honedge back: SirWhibbles

Inkay back: Chamber
Inkay front: COMBOY

Kirlia front:
Kirlia back: Koolboyman

Lairon front: bloodless
Lairon back: Koolboyman
Litwick back: COMBOY
Lunatone front: COMBOY
Lunatone back: COMBOY
Luxio front: bloodless
Luxio back: bloodless
Luxray front: bloodless
Luxray back: bloodless
Lycanroc Midday front:
Lycanroc Midnight front: JaegarLucciano
Lycanroc Midnight back: leparagon, devamped by Bummer

Mamoswine back: bloodless
Manectric front: COMBOY
Manectric back: bloodless
Mismagius front: ???
Mismagius back: Koolboyman
Morelull front: leparagon, devamped by Bummer
Morelull back: PokéCommunity's Gen VII: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer
Mudbray front: SupahSanti
Mudsdale front: leparagon, devamped by Bummer
Mudsdale back: leparagon, devamped by Bummer
Munchlax front: bloodless
Munchlax back: bloodless

Noibat front: SirWhibbles
Noibat back: PokéCommunity's Gen VI: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer
Noivern front: Maddalena
Noivern back: COMBOY
Nosepass front: COMBOY
Nosepass back: COMBOY
Numel front: bloodless
Numel back: bloodless

Oshawott front: bloodless
Oshawott back: COMBOY

Palpitoad front: bloodless
Palpitoad back: COMBOY
Pawniard front: COMBOY
Pawniard back: COMBOY
Pelipper front: bloodless
Pelipper back: bloodless
Phantump front: Dragonball253
Probopass front: COMBOY
Probopass back: bloodless

Ralts front:
Ralts back: Koolboyman
Ribombee back: leparagon, devamped by Bummer
Rockruff front: SupahSanti
Rockruff back:  leparagon, devamped by Bummer
Roggenrola back: COMBOY

Sableye front: bloodless
Sableye back: Koolboyman
Samurott front: N-Kin
Samurott back: COMBOY
Sawsbuck front: Maddalena
Sawsbuck back: COMBOY
Scolipede back: COMBOY
Sealeo front: bloodless
Sealeo back: bloodless
Seismitoad front: bloodless
Seismitoad back: COMBOY
Shellos front: bloodless
Shellos back: bloodless
Shiinotic back: leparagon, devamped by Bummer
Shinx front: bloodless
Shinx back: bloodless
Shroomish front: bloodless
Shroomish back: Koolboyman
Sigilyph back: COMBOY
Skiddo front: Vale98PM
Skiddo back: Gen VI 64x64
Skrelp front: Gen VI 64x64
Skrelp back: SirWhibbles
Snorunt front: bloodless
Snorunt back: Koolboyman
Snover front: bloodless
Snover back: bloodless
Skuntank front: COMBOY
Solrock front: COMBOY
Solrock back: COMBOY
Spheal front: bloodless
Spheal back: bloodless
Spiritomb front: COMBOY
Spiritomb back: COMBOY
Spritzee front: lakeofdance
Spritzee back: SirWhibbles
Staraptor front: bloodless
Staraptor back: bloodless
Staravia front: bloodless
Staravia back:
Starly front: COMBOY
Starly back: bloodless
Stunky front: COMBOY
Stunky back: COMBOY
Swalot front: bloodless
Swalot back: bloodless

Timburr front: bloodless
Timburr back: COMBOY
Torterra front: ???
Torterra back: bloodless
Toxicroak front: bloodless
Toxicroak back: bloodless
Turtwig front: bloodless
Turtwig back: bloodless
Tympole front: bloodless
Tympole back: COMBOY
Tynamo back: COMBOY
Tyrantrum back: PokéCommunity's Gen VI: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer
Tyrunt front: SirWhibbles
Tyrunt back: PokéCommunity's Gen VI: DS-Style 64x64 Pokemon Sprite Resource, devamped by Bummer

Venipede back: COMBOY
Vikavolt front: falgaia, devamped by Bummer

Walrein front: bloodless
Walrein back: bloodless
Weavile back: Koolboyman
Whimsicott back: COMBOY
Whirlipede back: COMBOY
Wingull front: bloodless
Wingull back: bloodless

Zorua back: COMBOY

Everything else not listed: Bummer