Some popular custom ROMs for Android 7.0 include:
This is the safest place to find ROMs.
: Search XDA Forums for your device model and "[ROM] [7.0/7.1]". Popular options from that era include LineageOS 14.1 . android 7.0 custom rom zip file download
: Though officially succeeded by LineageOS, many older ZIP files for specific devices still exist on XDA Forums OnePlus Community Some popular custom ROMs for Android 7