A total of 4 reviews of this product on Reddit.
You talking to me?
The ones that did not come with the board are: https://www.amazon.com/gp/product/B0919KTK2B/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
The arrow keys, esc, del, and spacebar all are red keycaps. I don’t remembrance they came from.
The spacebar is a Japanese wave design.
I just used some thin craft foam I had lying around and it made quite a difference. I cut it to it the individual impressions in the case, probably not actually necessary but I did anyway.
I used the most of the keys (letters, mostly) from the Corsair PBT set on Amazon (https://www.amazon.com/gp/product/B0919KTK2B/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) . Cheap and really pretty nice.
I have a mix of keys now, some original (mostly numbers and modifiers) some Corsair (letters PRTSCR and `~ ), and some custom (red keys, Arrows, ESC, and Delete). Some might think it a bit of a mess, but I like it.
Oh, and I remapped the Home, PgUp, and PgDown to Delete, PRTSCR, and `~ .