The ten most common flops of all probably contain a deuce. (Because of pre-flop hand selection, ace-high flops are the least common, and holecards containing a deuce are the least likely to see a flop, meaning that a 2 is slightly more likely to appear on the board).
But restricting your studies to boards containing a deuce isn't going to be very useful.
(
Spadebidder's studies showed that Aces make up only about 7.5% of the flopped cards instead of the 7.69% or 1/13 that a uniform rank distribution would yield, whereas deuces appeared around 7.8% of the time).
If you're making a list for study with Flopzilla/Equilab you should just aim to get a balanced mix of flop-types that is roughly in line with reality.
i.e. about 40% should be rainbow, 55% two-suited, and one in twenty is a monotone.
Of these, about 17% should have a pair on the flop.
Further dividing your flops into "two Broadways and a low card", "one Broadway and two low cards", "two connected cards and a blank (e.g. T93)" can give you a useful range of flops to study.
You can pretty much just write down a list of random flops and then check to see if you have too many aces, or not enough sixes or whatever, and then fix it to give roughly equal weighting to all the ranks.