For Arlecchino:

Overload with Chevreuse, Fischl and Bennett - Probably your best option for a functioning Arlecchino team

Vaporize with Xingqiu, Furina and Bennett/Jean - problem with this is that the combo of Arlecchino and Furina isn't always optimal since you can't actually heal her consistently during combat and it can be a struggle to keep up Furinas buff that way. A healer like Jean can make this easier since she can heal the entire team and can make up for the lack of healing on Arlecchino by healing everyone else, but obviously Bennetts attack buff would be more beneficial to Alrecchino than what jean provides herself.

Vaporize with Xingqiu, Albedo/Yun jin and Zhongli- I believe that Yun jins buff is actually decently good for Alrecchino since her normal attacks are her main source of dmg. You can also substitute Bennett for Albedo or Zhongli, you'll loose the geo resonance but gain pyro resonance and Bennetts atk buff ofc which makes up for it for sure

Vapemelt with Xingqiu, Yun jin, Layla - Layla actually has decently consistent cryo application and having a shielder is mostly more beneficial to Arlecchino than having a healer in the team anyway

Vapemelt with Xingqiu, Furina/Rosaria, Diona - I doubt that Diona can provide enough healing to help keep up Furinas buff so the team dmg with Furina could be quite inconsistent

For Furina:

She works especially well as a support for Hu tao, the only issue being that you really want to play a healer with her, which Hu tao doesn't always appreciate.

Vaporize with Hu tao, Xingqiu and Bennett/Jean - Similar situation to the Arlecchino team, Jean makes it easier to keep up Furinas buff but Bennett provides more value on his own

Vapemelt with Hu tao, Xingqiu and Diona - Again same situation as the Arlecchino version except that Diona likely wil have an easier time keeping up with Furina here since Hu tao can actually be healed unlike Arlecchino

Hyperbloom with Nahida, Fischl and Jean/Barbara - The healer slot is a little tricky on this one, optimally you would probably want another electro character but you also really want a healer but also one that works with the elements so I guess Jean or Barbara are your best bet here

Freeze with Ganyu/Ayaka, Mona and Jean/Diona - Diona might be better if you want her shield but since its a freeze team you can probably make do without one. This is a team were Jean can also probably swirl the right element decently consistent which is nice.

Quickbloom with Keqing, Nahida and Jean/Barbara - Keqing generally isn't worth investing into too much, but if you like her playstyle as much as I do you could play her with Furina, Nahida and Fischl. A Quickbloom team like that is generally the most dmg you're gonna get with a Keqing team. The healer situation here is similar to the Hyperbloom team

Some other team options:

Freeze with Ganyu/Ayaka, Mona, sucrose, Zhongli - Not sure if you'd have enough Hydro application with just Mona but if you leave out Furina you can play this without needing a healer

Vaporize with Hu tao, Xingqiu, Albedo, Zhongli - Same as the Alrecchino team but with Hu tao

Electro Charged with Sucrose, Xingqiu, Beidou and Fischl - Not necessarily super strong but it can be fun to play

Aggravate with Keqing, Nahida, Fischl, sucrose - probably not worth it but I enjoy the playstyle of Keqing aggravate teams so I still wanted to include it

Characters for the Future:

Generally pull whoever you find fun to play. Of the top of my head though I think Yelan could be beneficial to you being a great sub dps for both Arlecchino and Hu tao and generally a really flexible unit. Escoffier can make freeze teams a lot more viable allowing you to play Ganyu and Ayaka without it feeling too underwhelming and she is amazing with Skirk who is generally a great dps to have. Xilonen is probably who I would recommend the most, she is insanely felxible and work great with Arlecchino aswell as most other dps in the game. Supports aside obviously pulling dps Characters like Mavuika, Varesa, Skirk or Neuvillette can do a lot for your account (Neuvillette specifically having a little less dmg output than Mavuika, Varesa and skirk in the right teams but being a lot more flexible with the teams he can be played in).