$5 ?? None really
$10 FTH Macklem-Carney**, FTN Wilkins-Poloz, 2017 CDF
$20 BSW**
$50 AMK**, AMG
$100 EKZ**, EKY
Yes- the list above are the real tough ones to find in any condition but I would give these 3***. If you see one- hang onto it (graffiti and all). I have looked for years for these- so they're exceptionally hard to find. There have been 253 EKY so I would put that more in the 2** category (like AMG-177) considering everyone has been looking for them.
Now I'd give ** for
M/C GHD & AMG $50. I found a few but haven't seen any since (I suspect the low # GHD to be especially rare_. 51 M/C GHD $50 have been reported in SNDB (which is pretty low considering we've all been entering them for years now). I have found several circulated AMG $50 but I would be keep them in higher grade. The AMG inserts have rightfully shot up in value (likely because its so hard to get AMG in UNC).
and ** for
FVP $20 W/P around 1,000,000 have been reported printed but I suspect that # (likely printed in 90,000 blocks). Keep especially if you find in higher grades. These might also be a * for some members here who've found them in runs of UNC. I had a member anxious to sell me some in UNC..so maybe not as hard as we think.
Now for the * (worth keeping but don't get too excited)
$5 HBG M/C are keeper if you can find them in higher grades (I know these were dumped in certain parts of Canada but I never found any in UNC- had to source them through collector friends)
CDF $10 seem pretty quite hard to find out here in Ontario but yes they seem plentiful in Quebec. (keep higher grade)
FTN W/P $10 have been tricky to find but I have found a few UNC. FTU $10 have been much harder to get in higher grades (although there is a good chance FTU may still be released/some members have found bundles). If I found any in UNC I would be keeping them until it is determined how tough they will be).
FWW W/P $20 (non-commemorative) seem less common than the commemorative $20 (FVY seems to also be uncommon though it be could early yet and there may large dumpings yet)
Think that's it....