Dragalge

Dragalge is an interesting addition to Pokemon Go, featuring a Dragon/Poison typing and defensive stats. While this may not be useful for raids, it does make Dragalge a potential candidate for gym defense thanks to its resistance against common Fighting-type attackers. Whether Dragalge is actually worth the resource investment is another story however. 

Best PvE Offensive Moveset

• Dragon Tail + Outrage is the strongest moveset and benefits from STAB. 
• Acid + Sludge Bomb is passable if no other Pokemon are available. 
• Water Gun has no use.
• Hydro Pump is stronger than Aqua Tail, but consider actual Water-type Pokemon instead. 
• Focus Blast isn't very useful, and Gunk Shot falls behind Sludge Bomb in most cases.

Best PvE Defensive Moveset

• Dragon Tail is the strongest against neutral attackers due to its high base power. 
• Acid isn't particularly impressive, but can hurt Fairy-type attackers who forgot about Dragalge's Poison-typing. 
• Water Gun is too weak for defense.
• Aqua Tail can be used frequently as a 3-bar move, and also hurts Ground-type attackers.
• Outrage is a bit slow for defense, but hits hard if it isn't dodged. 
• Hydro Pump might not be accessible before Dragalge faints, but it's hard to dodge.
• Gunk Shot is a slap in the face for Fairy-types if it connects, partly due to its animation. 
• Focus Blast takes too long to charge up to be useful in most scenarios.

Acid provides Dragalge with the highest energy generation, while still outputting decent damage. Dragon Tail can be used for more Dragon-type damage, which can be preferable in metagames where Poison is heavily resisted. Water Gun lacks STAB and pales in comparison.

Aqua Tail costs the least amount of energy, and can be used frequently to pressure shields. Outrage is an expensive nuke that can delete opposing Dragon-type Pokemon. Sludge Bomb is a moderate cost STAB option that allows Dragalge to further punish Fairy-type targets, but Acid is usually strong enough to melt through them. Gunk Shot, Focus Blast, and Hydro Pump are all too expensive for serious use, though Focus Blast can surprise some Steel-type Pokemon.