Train, Release, Store in PC

Train Magikarp, Store Silvally, Release Uxie

Magikarp, Feebas, Arrokuda

Train Feebas, Box Arrokuda, Release Magikarp

Poliwag, Krabby, Lanturn?

Train Lanturn, Store Poliwag, Release Krabby. Likes Lanturn's status options. Expects more mileage from (likely) Poliwrath than Kingler.

Scatterbug, Fletchling, and Surskit

Train Fletchling, box Surskit, release Scatterbug. (Not interested in collecting all the Vivillon variants.)

Togedemaru, Mimikyu, Drampa.

Love Train Mimikyu, Box Drampa, Release Togedemaru

Pidgey, Spearow, Starly?

Train Mimikyu, box Togedemaru and release Drampa.

Snom, Qwilfish, Joltik

Train Snom, store Joltik, and ditch Qwilfish.

Breloom, Rapidash, Forretress?

Train Breloom!!!, Box Rapidash, Release Forretress

Geodude, Onix, Aron?

Train Geodude, Store Onix, Release Aron. Would not mind using Graveller (or preferably Golem) for a change. Already used Steelix a bit.

Silicobra, Buizel, and Murkrow

Train Murkrow, box Buizel, release Silicobra.

Espurr, Litten, Glameow.

Train Glameow, Box Litten, Release Espurr. Yup.

Seviper, Ekans, Silicobra?

Train Espurr, store Litten, and regretfully release Glameow. Sorry kitty. :'(

Edit: Ya beat me to it lmao. Train the silly cobra, box the backwards snake and release the viper.

Mimikyu, Omanyte, Deino?

Train Omanyte, Store Mimikyu, Release Deino. Never used Omanyte. Tried out Mimikyu a little before. Takes ages to get Deino battle-ready. (Did so once in X, though.)

Snubbull, Nincada, and Pidove.

Train Nincada yet again, store Snubbull, release the pigeon of Hell Pidove.

Ledyba, Surskit, Burmy.

Train Surskit, Box Ledyba, Release Burmy.

Zubat, Koffing, Grimer?

Train Koffing, Store Zubat, Release Grimer. Already used both Crobat and (Alolan) Muk. Made the choice easy.

Cutiefly, Torchic, and Horsea?

Train Torchic, box Cutiefly, release Horsea. Might have sung a different tune if Beta Kingdra had been canon, though.

Alcremie, Aromatisse, Slurpuff.

Train Aromatisse, Box Alcremie in case I get hungry, Release Slurpuff

Hypno, Jynx, Kadabra

Train Kadabra, box Hypno so it won't haunt anyone's nightmares, release Jynx.

Zigzagoon, Patrat, Yungoos.

Train Zig, Box Yungoos, Release Patrat

Panpour, pansage, pansear