Here is the full list of all 26 Volta-X achievements.
Complete the Season 1 Story.
Build all Voltas available in Season 1.
Recruit all crew members available in Season 1.
Fully level up one Part.
Qualify for the WVA.
Assemble all parts available in Season 1.
Assign the maximum number of abilities to a crew member.
Build a Garden in your Headquarters.
Research any technology to level 2.
Research all technologies to level 10 or above.
Have two crew members spend enough time together to max out a friendship.
Reach the Warrior League.
Win a battle by taking out all of your opponent's crew members.
Build a Headquarters with at least 1 of every room available in Season 1.
Bring all crew members in the Headquarters to a high level of happiness.
Change a crew member's costume.
Change a Volta's palette.
Completely fill a crew member's assignments in the Headquarters.
Light all rooms in an enemy Volta on fire.
Improve the quality of your food by using the Kitchen.
Complete all Season 1 Minisodes.
Witness a full band practice session.
Win a battle with only 1 part remaining.
Have all of your crew members use the Rocket Punch in one battle.
Break all Opponent's parts in a single battle.
Join a Clan.