When I saw this thread my thoughts went straight to Joltik.
But that's mostly because aventurine is filled with SPIDER webs, not Tick webs. Ticks don't make webs. So that's weird, finding Galvantula would simply make more sense.
BUT. Galvantula is EASY to grind up in Vanhanen Labyrinth. Just run from the Ponyta and Furfrou, Signal beam all Giraffarig and Deerling, which even underleveled it easily outspeeds.
Plus, I've taken a heavily underleveld Galvantula (like level 40) into the battle with Radomus once, it one shot both Malamar and Exeggutor.
On Houndour I agree, but on most level 1 Pokemon, such as Beldum and the eggs, easily trainable. they're level 20 after 3 Tauros/Bouffelant.
All the others are pretty much still in my pc unused.