I have sold to finance other things (like different pins) and have regreted quite a few sales. Mostly when you are just thinking about the past and not looking to the future. Have you thought about selling only the ones that you like the least - that way you shouldn't miss them as much. SWE1 and TS are 2 games that I won't miss. I would suggest you try to hold onto any that were valuable to you.
My daughter misses RFM, My wife kinda misses T3 (although she would never say it), and I miss NGG.
Like robertmee says
Quoted from robertmee:I've built a modest collection back up including a really rare pin in Mystery Castle
you can always sell and get something new later as desired.
