All of the above except RAC are the types of waiting list available with train booking. WL with a number suggests the waitlisted status of a passenger.
RAC means Reservation against Cancellation. If you have an RAC ticket, then your travel with a train is guaranteed but you will be given a seat (half of a side lower berth mostly) to sit and travel not an entire berth.
GNWL General Waiting List waitlisted tickets are issued to the passenger who begins his/her journey from the originating station of a route or stations closer to the originating station.
PQWL Pooled Quota Waiting List is shared by several small stations of a train route. The quota generally operates from originating station of a train route and only one Pooled Quota is there for entire run. The Pooled Quota is usually selected for the passengers travelling from the originating station to one or few stations short of the terminating station, or from a midway station to the terminating station, or between two stations coming midway of the entire route.
RLWL Remote Location Waiting List ticket is issued for the stations between the originating and terminating stations. Usually these are important towns or cities of that particular route. These tickets are given a separate priority and their confirmations will depend on the cancellations of a confirmed ticket. Remote location stations prepare their own chart 2-3 hours prior to the actual departure of train. There are less chances of confirmation for such waitlisted tickets.
TQWL Tatkal Quota Waiting List was earlier CKWL. It is the waiting list tickets booked under Tatkal Quota. TQWL tickets directly get confirm and don’t go through RAC. However, GNWL is given priority over TQWL.