695 Heliolisk

Volt Switch boasts the best balance overall of moderately high energy generation and decent damage output backed by STAB. Despite its very slow animation, it's the best fast move available. Quick Attack is a step down in every aspect, and can't be Super Effective against anything. Mud Slap is an alternative move that provides useful Ground-type coverage, but lacks STAB damage and has slow energy gains. 

Grass Knot is recommended for its valuable coverage against Heliolisk's weakness to Ground-type Pokemon, as well as its slightly lesser energy demands compared to the rest of its Charge Moves. Thunderbolt requires slightly more energy, but is the strongest move available against a neutral opponent thanks to STAB.  Bulldoze isn't a particularly good attack from a stats perspective, with moderately high energy costs, but can fulfill a niche in a scenario where an Electric Pokemon has an advantage in an Electric-type mirror.

Heliolisk is a unique Pokemon as an Electric/Normal type, but this typing isn't particularly synergistic. Heliolisk suffers from a poor stat distribution for PvP. High ATK does it no favors, lowering its overall bulk and ability to perform well in prolonged fights. The lack of any Charge Moves with low energy costs results in slower shield pressure than many meta Pokemon. Heliolisk's best niche is arguably its performance against other Electric-type Pokemon in a specific PvP format like GBL cups, with coverage against both Electric and Ground Pokemon. Just keep it away from the faster Electric-type Unova Stunfisk, as well as all Grass Pokemon period. 

Heliolisk's stats and movesets aren't very favorable for Ultra League, with the same issues as it had in Great League. It's no match for the various legendaries in open Ultra League, resolving it to restricted formats like Premier Cup to see any meaningful play. Electric and Ground coverage can be useful against popular Water and Poison Pokemon, but moderately high energy costs from Heliolisk's Charge Moves causes it to be too slow against various meta picks. Consider other Pokemon instead, at least until Heliolisk can get a moveset improvement in the future, maybe. 

The lack of stats is a major concern for any chance at Master League, as if its slow Charge Moves weren't enough of a drawback.