I really enjoyed the Zamor launchers, lore wise, the ammo made no sense, cuz the piraka's zamor couldn't enslave the Inika, and the Inika weren't about to shoot the piraka with energized protodermis spheres So they literally were only good for shooting at the Matoran (or at Brutaka to make him stronger). The other color spheres had cool powers, or you could make up your own powers so that was fun.
Cordak blasters were my favorite I believe, who doesn't love a revolving cannon that shoots explosives? Had a similar problem lore wise, as the Mahri, they couldn't use them effectively on the Barraki, but they were cool for the plot to destroy the cord.
Squid launches were a cool idea, but very badly executed. I still have a few squid that haven't broke I think...
Thornax were fun, having the small plastic band made firing them a bit challenging if the rubber got stuck on the launcher. Very unique and cool!
Nynrah Ghost blasters were also fun, but it was hard pushing the plunger hard enough for them to go really far.
Midak skyblasters were really cool! Hit hard, and accurately,
We never really lost our Rhotuka spinners (at least not permanently!) Those were fun to see how far up we could get them to fly.
I never really got into the 2015 stud launchers, but it's really easy to lose those tiny pieces. Still, it does shoot hard and fast, and works very well.