These patterns work on UID numbers only.
123$ . ends with 123
(123|456)$ . ends with 123 or 456
789 . includes 789 anywhere
(789|456|012) . includes any of 789, 456, 012
^203.*123$ . starts 203 and ends 123
(?=.*789)(?=.*12) . includes 789 and 12 in any order
^(?!.*999).* . matches UIDs that do not contain 999
(11|22|33|44)$ . ends with double digits like 11, 22, 33, 44
(\d)\1 . has any repeated digit like 00. 11. 22 etc
(?=.*45).*78$ . contains 45 and ends with 78
If regex is invalid, search will fall back to normal contains search.