You could use the blocks as they are, but I wanted some handles on mine, so a visit to B & Q yielded these:
Small wooden handles, a pack of ten was £9- you can get a similar handle in plastic for about a fiver.You can see they come with screws, so Beloved Hubby drilled through the blocks for me (probably safer than me doing it), and screwed on the handles.


Next bit was to add Velcro, and a good cheap source for this is market stalls- especially if you are not fussy about the colour- black & white are the ones most people buy, so if you look round you will often find other colours a lot cheaper. This one I used is a sort of flesh colour, and cost me about 25p a metre- although I still always ask for a yard of something, lol. Gets me some odd looks.
So I cut some pieces to fit the blocks- and you want the 'hook' side for this,(the stiffer, rougher side) not the loop (the fluffy one). I used a hot glue gun to attach this to the block, and I found it was better to do two sides, attach the velcro, then do the other two sides. Press down well, especially the corners.

I tidied them up after, cutting away any excess glue.What I haven't done with these is add a layer of foam, which the original blending tools have. I figure they are going to have a foam pad attached, so don't need it. If I'm going to use felt & alcohol ink, then I'll use my originals. I had a browse around the net before I started, and it seems some people do add the foam, some don't.



I tidied it up after, trimming any overhang away with a scalpel.
So here are all my new blending tools:
A later edit:
I recommend stapling your velcro to the wooden block, rather than using the foam tape. I found it started to lift after peeling foams/felts off a few times.