I know about the 'related tracks' and 'matching' feature in Rekordbox however I find that it would be very simple if Rekordbox had the option to create a playlist of track pairs. A playlist of several sets of 2 tracks that mix well together. Granted you can do this already on your own by adding multiple track pairs to a playlist -- but then you just have tacks numbered sequentially (5 track pairs would be listed track 1-10). You would have to remember that tracks 1 and 2 are a pair, 3 and 4 are a pair, 5 and 6 etc. A pair playlist could that the devs could create is one that shows the first two tracks as 1, second pair and 2 third pair a 3 and so on. Or just create a highlight for each pair in different color shades. I just find that being able to look at a playlist to find pairs that go well together is much easier than trying to navigate a related track match. If there was any way to do this through the related tracks playlist settings I would be all over it - but they only give you the option to match tracks with specific attributes like pitch percentage, key etc.
A rough example of what I'm referring to:
Track Pairs Playlist:
- Track
Track
- Track
Track
- Track
Track
Each set a pair in one playlist.
just my 2 cents.