I used to use K-L-N regularly. It contains synthetic auxins, IBA and NAA. (Superthrive contains one of them...I think it's NAA). If fresh (the synthetic hormones degrade fairly rapidly), it can be a powerful root-growth stimulant, but there is the risk of overdosing it, leading to flower deformities.
Clonex is a very dilute fertilizer that has thiamine (vitamin B1) added. B1 has been shown to have some stimulant effects, but it's really not all that powerful.
If you want a truly remarkable, yet safe stimulant, consider
KelpMax.