For the most part, Venusaur’s counters depend on what set it is running. The physically inclined set counters depend on what Venusaur is using to complement Power Whip. If Venusaur lacks Earthquake, Registeel can counter Venusaur pretty well, especially if Sleep Clause is in effect. However, if Venusaur lacks Return, a defensive Moltres is the safest switch in to Venusaur. For the specially inclined sets, Chansey and Registeel are the best checks to Venusaur.
~strat-dex
~strat-dex