@Sqribbz is getting encounters in his nuzlocke based on poll answers. But since we wanna give him a rough time, here's what we should vote for! Keep in mind species clause applies.

Route 1: Twilat

Neither of its evolutions are useful and it stops an encounter at the Pagoda.

Gale Forest: Propae

A weak bug-type that falls off after beating the second theatre. Propae is also annoying to level up as opposed to Cathorn.

Route 3: Geklow

While paralyzing Loomians is useful, it's very tough to obtain a Thunderfruit.

Route 4: Slugling

Gastroak is actually quite useful due to its bulk. You're guaranteed to get one in Kanoko Village so getting one here is disadvantageous since you can't get anything else on Route 4.

Route 5: Gumpod

A bulky water-type is useful, but it has poor offenses and everything else on the route outclasses it.

Igneus Hollow: Craytal

Skilava and Igneol are both excellent at their final forms. If Volkaloa is allowed, Craytal becomes quite useful, but still not as good as either of the others.

Heiwa Village: Eyebrella

Lantorch is fast and strong, Biwarned gets conclusion, Rancidor has a good matchup against the 4th theatre, which leaves Eyebrella.

Heiwa Cemetery: Grubby

Both the spirit-type Loomians here are useful in some way, leaving Grubby.

Route 6: Kabunga

Wiki-Wiki is absolute garbage. Chartiki, if allowed, is somewhat helpful, but not more helpful than anything else on the route as the Cafnote line has raw power and Gobbidemic has useful speed.

Route 7: Chompactor

Rev Up is an excellent ability but you're not guaranteed to get it. Even still, its stats aren't great.

Sepharite Junkyard: Sherbot

It has unfortunately poor stats for a fully-evolved Loomian.

POLUT Corp: Poochrol

Hunder without an SA and rallying moves isn't nearly as useful as Gardrone's vast coverage.

Route 8: Ampole

Meditoad is quite bulky and useful with its electric coverage, but once again, it's hard to obtain a thunderfruit.

Route 2: Goppie

Just to stop you from getting Swimp and an encounter in Bob's Pond.

POLUT Underwater Mining Lab: Kyogo

A useful but frail support Loomian. All the other fossils have better story matchups (even Infernix who matches up well against Frostveil).

Lotusun Beach: Cavenish

Banfino has useful plant coverage and healing, but is on this list since every other encounter outclasses it.

Atlanthian City: Fentern

A very frail Loomian that doesn't do much without its SA. Using up the Kabunga Coffee is also a pain.

Atlanthian Arcade: Boonary

It's the only encounter you can get here.

Aranatta Trench: Singeel

It can't evolve without another Singeel so it's basically useless.