Wildcard character in a SCCM task sequence like clause

This actually depends on where you want to use the query. If it is in a query for a collection % is correct. The same is true if you want to use a wmi query within a TS step. Both of these fall back to WQL where % is the wildcard character.

However if you use a condition on a TS Variable (or collection variable) the correct wildcards are * and ?. This is undocumented but confirmed by the ConfigMGrTeam (see here, and here)