I've been trying to create amazing teams in ranked to win team fights every time. Here are the champions I've thought of for each role, from best to worst. If you have any other suggestions, leave them below.
Top: Wukong, J4, Jungle: J4, Wukong, Mid: Orianna, Ziggs, Brand, Talon ADC: Miss Fortune, Graves, Ezreal, Support: Leona, Sona, Braum, Taric, Morgana
malphite+orianna is pretty sick in a team fight.
like literally if malphite presses R and ori presses R in a good ult. the entire enemy team is 25 pct hp.
Captain Falcon and Fox
Top - Malphite Jung - Amumu Mid - Orianna or Ziggs (Morgana) ADC - Miss Fortune or Jinx Support - Leona or Sona (Morgana)
Amumu dives in with Ori ball, ults. Ori and MF ult together, grouping and spraying damage, while Malph and Leona ensure everyone stays put.
Alternatively, initiate with Malph/Ori ults, follow-up with Amumu/MF ults.
If using Ziggs and/or Jinx, fire it when the first CC block hits.
To add to your list up there in mid lane Katarina, and as adc jinx or corki. All have very nice synergy with the other picks there as an all in teamfighting comp.
Amumu is a must for a wombo-combo if your APC has a big AOE ult. Amumu reduces the magic resistance of enemies near him, so the APC deals additional damage with their ult.
TOP: 
JG: 
MID: 
ADC:
or 
SUP: 
or 
R, R, R, R, R
rift explodes
