A lot of them have had special uses and non-standard equipment, most of them known only internally. You could fill a whole page if you looked at fleet number font variations. Here are a few off the top of my head to get you started. If you really want to make a comprehensive list, start researching, there's a lot history before 2014 to be found.
4000 - 1984 Celebration Ontario Bicentennial (yellow)
4002 - 1984 Celebration Toronto Sesquicentennial
4005 - 1984 Celebration Ontario Bicentennial (blue)
4031 - last car with couplers in 1988
4024 - chartered by Dave Stewart of Eurythmics for tour promotion 1990
4046 - WSIB all-black remembrance car in 2018
4063 - used to carry Saudi prince to CNE for special Saudi Arabia exhibit 1991 (I think).
4072 - used in official opening for 509 in 2000
4089 - air conditioning prototype- removed after test period
4093-4106 equipped with radios for night car service before CIS (up to 1990).
4134 - first ever wrapped CLRV, for Starbucks in 2000
4136 - clearance test car for roof-mounted air conditioning (type used on 4041)
4140 - at 514 opening June 2018
4145 - last one in service with original gold-tinted windshield
4165 - first CLRV to receive LED taillights
4175 - to be used for 1984 celebration, paint adhesion problems, first CLRV repainted that wasn't one of the celebration cars
4205 - used in official opening of 509 in 2000
4238 - protoype air-conditioning later removed
4240 - first ALRV with LED taillights
4251 - first wrapped ALRV, for Starbucks (similar to 4134)