We really do love the ease, gentleness, and availability (everywhere!) of Blue Dawn. But in case you want to try the "pro" stuff, here are some links to get you started. A little goes a long way, for all of these.

Dharma's PTD (generic version of synthropol) $3.95+

Synthropol, 8 oz., Jacquard (Dick Blick) $8.99

Synthropol, 32 oz., Jacquard (Amazon) $19.85

PROsapol ("professional Synthropol"), 16 oz. 18.95 €

Blue Dawn, 21.6 oz. (Amazon) $7