poliwag: tynamo (amorph/aquatic/electric regions) spheal: dratini: part of the dragon package totodile: water/aquatic lotad (grass/aquatic/sound regions) goomy: key part of the dragon package corsola (rock/aquatic regions) blue shellos (rock/aquatic regions that are not water or ground) sobble

tentacool seal corphish anorith bidoof skrelp clobbopus

wooper: tanky frontliner paldean wooper (poison region): tanky frontliner surskit croagunk chewtle tadbulb

buizel cubchoo inkay

lapras: frontliner. ice? quilfish: water/aquatic. hisuian quilfish (dark region): can hold critcast? luvdisc: water/aquatic synergy is nice, can super highroll depending on what components you get. cramorant: pincurchin: dracovish: fantastic synergies. dragon allows you to hit aquatic 8 as early as level 6 (dracovish, goomy, dratini, +3). This can also enable a fossil angle, particularly if tyrunt is added. arctovish

lugia manaphy + phione keldeo volcanion ogerpon wellspring (aquatic region)

tympole: froakie: generally just a good water/aquatic synergy filler in aquatic

surfing pikachu:

notable non-aquatic pokemon: horsea gyarados palkia walking wake

kyogre

kecleon arceus popplio