There are 14 designs [through 2019] of indicia whose face value is "FOREVER". Each design is distinctive enough that it can be identified by examining the images below.

Liberty Bell design U199 You have identified design #U139 diagnostic for Scott #U667 (multicolored on white paper)   purple martin design U204 You have identified design #U139, multicolored on white paper and shared by Scott #U677 (design size 33mm x 48mm) and #U678 (35mm x50 mm)   Bank Swallows design U205 You have identified design #U139 diagnostic for Scott #U680 (multicolored on white paper) size 38x35mm; or size 41x38mm and diagnostic for Scott #U681.   Eagle, shield & flags design U206 You have identified design #U206 diagnostic for Scott #U682 (multicolored on white paper); or double impression of magenta diagnostic for Scott #U682a; or triple impression of light blue diagnostic for Scott #682b.   Poinsetta design U207 You have identified design #U207 diagnostic for  Scott #U684 (multicolored on white paper).   Snowflake design U208 You have identified design #U208 diagnostic for Scott #U685 (multicolored on white paper).   Showflake design U209 You have identified design #U209 diagnostic for Scott #U686 (multicolored on white paper).   Cardinal design U210 You have identified design #U210 diagnostic for Scott #U687 (multicolored on white paper).   Child making snowman design U211 You have identified design #U211 diagnostic for Scott #U688 (multicolored on white paper).   Red Water Lily design U212 You have identified design #U212 diagnostic for Scott #U690 (multicolored on white paper).   White Water Lily design U213 You have identified design #U213 diagnostic for Scott #U691 (multicolored on white paper).   Forget-me-nots design U214 You have identified design #U214 diagnostic for Scott #U692 (multicolored on white paper).   Northern Cardinal design U215 You have identified design #U215 diagnostic for Scott #U694 (multicolored on white paper).   Barn Swallows design U216 You have identified design #U216 diagnostic for Scott #U696 (multicolored on white paper).