Here's a team I've been using since Day 1 that has some synergy I like.
I usually lead Maushold. When people see Maushold lead, they think oh ok another PopBomb team, here we go again. But I'm actually more interested in Maushold's other signature move, Tidy Up!
Hazards? What Hazards? Tidy Up removes all hazards on your side, can't be blocked by Clear Body, Good as Gold, Ghost or Steel Types, and acts as a free dragon dance! Greedy Hazards setters may sometimes keep setting up on you, but this only boosts you more. PopBomb has sometimes won me games by itself or tore out half of the team by the time the Nice Mice™ die. It can also synergize well with other moves that are passed onto it, such as Mach Punch, Scale Shot and Icicle Spear, thanks to Technician, but unlike PopBomb, keep in mind all hits aren't guaranteed.
The three offensive sweepers on the team appreciate a nice little Dragon Dance with Benefits™, but the main character of this seasonal anime is Breloom. With Technician and Loaded Dice, it takes Bax and Moon's Icicle Spear and Scale Shot respectively, and elevates them to new heights! Tidy Up gives it a much appreciated speed boost, while also increasing its attack power and removing hazards! It passes Mach Punch to its teammates, but honestly force palm could be passed here if you want to keep maushold alive.
Flintstone Salamence Works well to ward away psychic types, appreciates its little Draconic Boogie from his little rodent friend, and passes scale shot to the rest of the team. Gave it Roseli Berry and Iron Head for coverage and fairy resist, in case you wanna sweep. Worst case scenario, Bax and Breloom gain a dangerous new move.
Decided to grab Bax as an Icicle Spear user not only due to his strength, speed and bulk, but also because he appreciates receiving moves such as scale shot and bulk up. I gave him the dice to synergize with iSpear and Scale Shot better, but if you wanna give him, like, life orb, lefties, or a lunchbox with a ham-jam sandwich, I'm not the boss of you so go ahead.
Those four are the core of the team to me, and I realized I needed some defensive and special options as well. However, I couldn't think of any defensive or special mons that would synergize well with multi-hit/technician/tidy up, so I tried multiple combinations and this is what stuck:
Clod is there not only so we can pay our respects to Him, but also for unaware, Garganacl, and passing haze to Klefki. It's specially defensive but can take some physical hits pretty well.
Steel Fairy is great defensive typing, and with max HP and Defense investment and access to Reflect, Klefki can take a lot of hits. Prankster is its main appeal here, but it can also wall out physical attackers that aren't bear-shaped and know kung-fu.
I think the team can be improved, but I don't know how or what. Nevertheless, it is a lot of fun, and I highly recommend giving it a try!