roasted way more pimento peppers than I need. Can I freeze them or otherwise preserve them? For how long?
Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
You can store them in a little olive oil in a covered container in the refrigerator for two, maybe three weeks; the taste and texture will be fine.
For longer storage, lightly film a cookie sheet with an oiled paper towel. Place a single layer of peppers on the sheet and freeze them. When they're solid, put them in a plastic bag and store in the freezer for up to three months.
A friend once brought me a bag of fire-roasted mild chiles from New Mexico--they still had the skins on. She told me to freeze them and I did and they were fine. The skins just fell right off when I defrosted them and they were good, even for chiles rellenos.