Multi Sport Fighters

Here are 20ish fighters who competed in multiple Combat Sports.

Semmy Schilt: 
Kick Boxing: 43-6-1 (20 ko)
MMA: 26-14-1 (15 ko 9 sub)
combined record: 69-20-2 (35 ko 9 sub)

Mirko Cro Cop
Am Boxing: 48-8 (31 ko) 
Kick Boxing: 26-8 (13 ko)
MMA: 38-11-2-1 (30 ko 4 sub) 
combined record: 112-27-2-1 (74 ko 4 sub)

Ben Askren
MMA: 19-2-1nc (6 ko 6 sub)
Wrestling/Grappling: 195-20
combined record:214-22-1nc

Igor Vovchanchyn
Am Kick Boxing: 61-2 (48 ko)
MMA : 56-10-1nc (41 ko 7 sub)
combined record: 117-12- 1nc (89 ko 7 sub)

Israel Adesanya:
Am MMA: 0-1
MMA: 20-0 (15 ko)
Boxing: 5-1 (1 ko)
Kick Boxing:75-5 (29 ko)
combined record: 100-7 (45 ko)

Alistair Overeem:
Kick Boxing: 10-4 (7 ko)
MMA: 47-19-1nc (25 ko 17 sub)
combined record: 57-23-1nc (32 ko 17 sub)

Donald Cerrone: 
Boxing 0-1
Kick Boxing: 28-0-1 (19 ko)
MMA: 36-15-2nc (10 ko 17 sub)
combined record: 64-15-1-2nc (29 ko 17 sub)

Butterbean:
Am Boxing: 47-5 (36 ko)
Boxing: 77-10-4 (58 ko)
Kick Boxing: 3-4 (2 ko)
MMA: 15-10-1 (8 ko 7 sub)
combined record:

Jairzinho Rozenstruik:
MMA: 11-2 (10 ko)
Kick Boxing: 76-8-1 (64 ko)
combined record: 87-10-1 (74 ko) 

Duane Ludwig:
Am Kick Boxing: 12-2 (9 ko)
Kick Boxing: 14-7-1 (5 ko)
MMA: 21-14 (10 ko 6 sub) 
combined record: 47-23 (24 ko 6 sub)

Melvin Manhoef:
Kick Boxing: 38-14 (27 ko)
MMA: 32-15-1-2nc (29 ko)
combined record: 70-29-1-2nc (56 ko)

Chuck Liddell:
MMA: 21-8 (13 ko 1 sub)
Kick Boxing: 22-0 (18 ko)
combined record: 43-8 (31 ko 1 sub) 

Mark Hunt:
MMA: 13-14-1-1nc (10 ko)
Kick Boxing: 30-13 (13 ko)
Boxing: 0-2-1
combined record: 43-19-2-1nc (23 ko)

Sergei Kharitonov:
Boxing: 1-0 (1 ko)
Kick Boxing: 7-4 (5 ko)
MMA: 30-7-2nc (20 ko 8 sub) 
combined record: 38-11-2nc (26 ko 8 sub)

Holly Holm;
Boxing: 33-2-3 (9 ko) 
Kick Boxing: 14-1-7
MMA: 14-5 (8 ko)
combined record: 61-8-10 (17 ko)

Joanna Jedrzejczyk:
MMA:16-4 (4 ko 1 sub)
Kick Boxing: 27-3 (4 ko)
Am Muay Thai: 37-3
combined record: 80-11 (8 ko 1 sub)

Maurice Smith
Boxing: 0-1
Kick Boxing: 53-13-5 (23 ko)
MMA: 14-14 (8 ko 3 sub)
combined record: 67-28-5 (31 ko 3 sub)

Jame McSweeney:
MMA: 46-7 (31 ko)
Kick Boxing: 15-18 (9 ko 6 sub)
combined record: 61-25 (40 ko 6 sub)

Bas Rutten:
Kick Boxing: 14-2 (14 ko)
MMA: 28-4-1 (12 ko 13 sub)
combined record: 42-6-1 (26 ko 13 sub)

Edson Barboza:
Kick Boxing: 25-3 (22 ko)
MMA: 21-9 (12 ko 1 sub)
combined record: 46-12 (34 ko 1 sub)

Paul Daley:
Kick Boxing: 21-3 (14 ko)
MMA: 41-17-2 (33 ko)
combined record: 62-20-2 (47 ko)

* Edited at 03.06.2021, 10:06 PM ET *

Edit, Izzy is 20-1