So now that I made a witch and guard, I looked for a 10x8 board. I didn't realize they're hard to find. (One was $950 which is way too expensive for me). But after some searching I finally found a 10x10 board. It's an old draughts board, and the condition isn't perfect, but I think it matches my pieces. I can block off two ranks to use it for 10x8. Here's the complete bulldog setup (with witch and guard). I still have to make the black pieces.
List of unconventional pieces.

I need to finish the black pieces, and then we can have the first-ever bulldog game with actual wood pieces. But I'm in Ohio, so it will be a long drive. I might play my brother first (he lives closer).

garden snail: can move only one tile in any direction (just like the king) and can't be destroyed and not affected by check

The Dabbaba can move two squares vertically or horizontally, and is a leaper. It is seen in some old chess variants such as tamerlane chess.
10x10 boards can be ordered in many qualities and price classes:
https://www.raindroptime.com/checkers-and-draughts/checkers-material/checkerboard.html

Henk from Superchess used to sell 10x10 boards with large squares. The issue with checkerboards is that the squares are good for draughts stones, but too small for chess pieces. They do fit but it's not a nice ratio.

Henk from Superchess used to sell 10x10 boards with large squares. The issue with checkerboards is that the squares are good for draughts stones, but too small for chess pieces. They do fit but it's not a nice ratio.
In House of Staunton, i think that the squares are 2.25 or 2.5 inches !!
That's a good size for chess pieces!!!
Chess piece sets come in many sizes, and for variants with large boards and many pieces, having the pieces too large is often not an advantage. The Superchess pieces are pretty large, (after all, they were designed for an 8x8 game), but I think they still fit quite well on the Draughts board that is on the back of my Chess board:
Superchess pieces (plus some of my own handiwork) on a wooden Draughts board
I suppose so, as they are still offered on the Superchess website. (Click 'available pieces' or 'order form' on the left; tehse do not seem to have independent URLs.)

...I love your design of the Guard. Very nice.
Thanks!. Making the pieces from wood took a lot of time, including carving the spikes and gluing them together, and adding to parts from a rook. I have a friend, and he might help me produce some 3D printed pieces. If we finish I'll post some pics.

...10x10 and 12x12 boards are available on house of staunton...
HGMuller
...10x10 boards can be ordered in many qualities and price classes:
Thanks Musketeer and HG Muller.
Unfortunately I've been looking for a 10x8 board. I have found some commercially but they're more then $500 (US). What I did for now is buy a 10x10 board, and added a mask on two ranks. This give me the 10x8 playable area:
...This guy's carved this shogi variant set out of wax resin...
Wax resin is a good idea - probably easier than wood.