How many ways the Democrats could regain control of the US Senate in 2020? [View all]

1) Republicans nominate Moore(R-AL) and Kobach(R-KS) +1D
Democrats pick up:
CO(Gardner-R vs Hickenlooper-D) +2D
AZ special(McSally-R vs Kelly-D) +3D
NC(Tillis-R vs Cunningham-D) +4D
2) Republicans don't nominate Moore(R-AL) and Kobach(R-KS) -1D
Democrats pick up:
CO(Gardner-R vs Hickenlooper-D)0D
AZ special(McSally-R vs Kelly-D)+1D
NC(Tillis-R vs Cunningham-D)+2D
ME(Collins-R vs Gideon-D)+3D
IA(Ernst-R vs Greenfield-D)+4D