Help researching a new coin series to start collecting
I need a bit of a change of plans with coin collecting and perhaps researching a new set prior to collecting is what I need.
What's a coin series that is not too long to complete, not too financially difficult to complete (IE-affordable keys/no stopper dates), looks good in mid-grade circulated ranges (if needed due to budget constraints), and will give the collector enjoyment during the process.
Cannot be modern(post-1965). Would consider non-US coins too.
Thanks in advance for the suggestions!