What do you mean by 'here'? In the Leo article or in the Piececlopedia?

I think the Piececlopedia is currently only used for descriptions of individual pieces. And that to qualify for an article a piece must have some importance, like participating in a well-known variant, enjoying a large popularity in many less important variants, or being archetypal for a certain class of pieces.  AFAIK there are no articles that describe entire classes of pieces.

I would not be against having some of the latter, though. E.g. having an article on ski-sliders, which would describe the general principle, mention Ski-Bishop, Ski-Rook and Ski Queen, and the Tenjiku Shogi Heavenly Tetrarch, which is a compound of historic importance including this move. Or an article about slip-sliders. Many of the pieces that could be addressed in such 'overview articles' would not be worthy of having their own article, but it would still be nice if articles on occasional variants that use them could refer to a piececlopedia article, rather than each having to explain the principle of a ski-slide again.

We should be careful not to overdo it, though, and refrain for elaborating on the obvious. That you can make compounds of any set of pieces, and that these pieces do not necessarily have to have moves that fall in the same class, can be considered understood implicitly. The Rook-Vao and Cannon-Bishop compounds are examples of slider-hopper compounds, but I don't think they are of much interest otherwise. I haven't seen them used in any variant (which might not mean that much, as my knowledge of variants is far from enceclopedic), which would make them just as theoretical as zillions of other conceivable compounds. In other words, not even worth mentioning in an article about another piece or move class.

It seems to mee that the Piececlopedia currently contains some articles that would be rejected for not satisfying the criteria I mentioned if they would be submitted now. E.g. there are articles about The Zig-Zag, Zag-Zig etc. I am not even sure it would make sense to present the four pieces that are mentioned there in one article as a special class. They are just examples of asymmetric sliders, (of which there is an infinite number), and furthermore all the same piece after rotation / mirroring. There are hundreds of examples of not fully symmetric sliders, all of far more importance because of their appearence in Shogi variants, but they can all be described as handicapped Queens, not being able to move in some of the 8 directions. (In principle there exist 255 pieces that satisfy this description, if you count reoriented pieces as different.) I don't think it would be a good idea to devote a separate article to each of those, not even for the White Horse and Whale, which appeared in one of the most successful chess variants of all time (Chu Shogi). It might be an idea to devote a single article for discussing asymmetrically handicapped Queens, pointing out various types of asymmetry breaking (horizontal and vertical mirroring, rotation, inversion), together with a table listing the names of the mroe important ones. (Which then definitely would not mention Zig-Zags...)

Another issue I had with existing articles was Piececlopedia article for the Griffon. IMO it devoted an unduly large amount of attention to the 'Hippogriff', a lame mult-ski version of teh Griffon that seemed ever only used in Tamerlane Chess, but not under that name. There are many other pieces that do move to a sub-set of theGriffon target squares, which seem equally or more deserving of mention than this Hippogriff. Such as a variety that skips the F square (i.e. starts with a Knight jump), or a variety that cannot move to it, but can be blocked there. And the 'Spotted Griffon', which can only move to odd squares on the Griffon path (or was it even?). Perhaps none of them important enough for a separate article, but certainly worth to be mentioned.