From Valve Developer Community
incrementvar CVAR MINVALUE MAXVALUE DELTA
- CVAR: a console variable we want to change.
- MINVALUE: a minimum bound for our variable.
- MAXVALUE: a maximum bound for our variable.
- DELTA: the amount to increase CVAR by. Set this to a negative number to decrement.
Note:Incrementing a variable past the MAXVALUE specified causes the variable to loop around to the MINVALUE. The same happens the other way around, too.
BindToggle, a console command that works off this one.