Is it possible to add a wildcard to the end of a string?
Until you elaborate, I’d say the answer is NO.
Here is an example: I am in the process of making a Workset manager for MEP equipment I was wondering instead of having to filter by “Hydronic Supply” and “Hydronic Return” to eliminate element down to the certain Worksets is it possible to do it by just "Hydronic"with wildcard on the end so that I just need to do it once? I have a couple of areas of which I need to do this. 
Here are a couple other options… I would also really love to actually have wild cards in dynamo, I have seen some workarounds, but there should be a simple way.
Thanks guys I have taken what Timon send and created a custom node. just wanted to share it with you. Filter Element Wildcard