Is the Harmonizer you recieve when you pick Summoner the only weapon available right now? Is it worth enhancing?

You should still get it to +30 because it has a potential (I believe that it is an increase to healing). Most Harmonizers/Takts on the JPN server are 13☆+ and are related to specific content that we don't have yet on the NA server (like Ultimate Quests or Buster Quests), so it's likely they haven't added many/any yet, though in general your Pets and their Candy Box are going to be what you focus on more as a Summoner.

Where can I rebuy a harmonizer? I sold the one from Pietro, not realizing it was a requirement for summoner! Weapon shop doesn't show its available.

@camascosauce said in Summoner Harmonizer only weapon?:

Weapon shop doesn't show its available.

I've had this problem with non-new class (Pre-Summoner/etc.) weapons (IE: No Assault Rifle) as well on the JP version. For some reason, I've seen it vary depending on what class/character I choose to come to the weapon shop as, as well as when I sell/buy weapons from the NPC. There's no explanation as to why this occurs.

make a new character as a summoner then talk to Pietro that will give you 2 harmonizers put in shared bank delete that character (takes 24 hours to delete) make a new one, repeat until harmonizer is at 35+

There is also a Weapon merchant in the shopping area

@camascosauce Don't know if you've solved it, but you can buy one from the personal shop for pretty cheap.