Gumshoos

Damn, look at those teeth! While it's better to avoid getting bitten by Gumshoos, it's even better to avoid powering it up due to its lackluster performance in the meta. 

Best PvE Offensive Moveset

• Bite synergizes with Crunch to fulfill a Dark-type role. But maybe just use a Dark-type Pokemon instead.
• Take Down can't be Super Effective.
• Hyper Fang can't be Super Effective.
• Rock Tomb has no STAB nor synergy. 

Best PvE Defensive Moveset

• Take Down gets STAB and deals more damage against neutral attackers.
• Bite will very likely be resisted by ubiquitous Fighting-type attackers.
• Crunch can be used frequently as a 3-bar move, but is more likely to be resisted.
• Hyper Fang is good against neutral attackers.
• Rock Tomb has useful coverage, but not against common Fighting-type attackers.

Bite is the only reasonable Fast Move, giving Gumshoos a niche vs Ghost Pokemon.

Crunch costs the least amount of energy, which is important given the lack of fast energy generation, and helps Gumshoos wall Ghost-types even more. Hyper Fang costs slightly more energy and benefits from STAB, making it decent for neutral opponents, but can't be Super Effective against anything. Rock Tomb's coverage can be valuable, but its energy cost is very difficult to ask for.