SPE and DPE are different types of ball valve seats.

Ball valve with DPE (Double Piston Effect) seals both at upstream or/and at downstream. When ball valves with DPE seats needs to achieve cavity over-pressure automatically, a extra pressure relief device need to be installed.
Ball  valves with SPE ( Single Piston Effect) seals only at upstream. And will release the cavity over-pressure automatically to the pipeline.

DBB ( Double Block and Bleed) and DIB(Double Isolation and Bleed) are different forms of valves.

The ISO/API definition of DBB reads as follows: "single valve with two seating surfaces that, in the closed position, provides a seal against pressure from both ends of the valve with a means of venting/bleeding the cavity between the seating surfaces".  The definition for DIB reads as follows: "single valve with two seating surfaces, each of which, in the closed position, provides a seal against pressure from a single source, with a means of venting/bleeding the cavity between the seating surfaces".   The definition of DIB isn't very clear all by itself, so it's best to read it concurrently with the requirements of the DIB testing in Annex B for clarification.

In short, DBB is valve with both side SPE seat, and DIB-1 is valve with both side SPE seat, and DIB-2 is valve with one side SPE seat and one side DPE seat.

DIB-1 is a test performed on a valve where both seats are uni-directional (DPE) and a DIB-2 test is performed on a valve with one seat uni-directional (SPE) and one seat bi-directional (DPE).  Both DIB-1 and DIB-2 are optional tests, and must be requested in order for the test to be performed.  So, either a DIB-1 or a DIB-2 test will test the effectiveness of a DPE seat.

DBB Trunnion Mounted Ball Valve