My idea is Gobliniods species with Goblin, Hobgoblin, and Bugbear lineages since they are supposed to all.be related like Elves are to each other (Sea Elves, Shadar Kai, Eladrin, High Elves, Wild Elves, Drow, Astral Elves can be physically and magically very different from each other, like Gobliniods, except for size differences), Fey Ancestry can be a shared trait.
I can see goblins getting the PHB treatment for various reasons, but bringing in the full set of goblinoids seems less likely to me.
Orcs fill a kind of visual niche that the '14 PHB only really had through the inclusion of half-orcs (which have now evaporated into the aether, as we all know), and goblins can fill a similar niche for small-sized characters that "legally-distinct hobbit" and "garden fixture" don't really cover. But trying to work in bugbears and hobgoblins as well just muddies the orc's place in the lineup. There's a meaningful difference between "big orc" and "small orc", but not so much between "big orc", "slightly less big orc", and "big, furry orc".
It also starts to run into the same kind of issues you'd have if the PHB elf entry were forced to cover every kind of elf (high, wood, dark, sea, eladrin, shadar-kai, astral, etc.). After a certain point, option variety and page space becomes a concern. Goblins are one extra page to the line-up. Goblinoids would be three. Gith would be two, and genasi four.
The more that are added, the larger the species chapter of the PHB balloons and the less distinct any individual option in the lineup becomes, even if there are compelling reasons for a given option's inclusion. We already have human, elf, dwarf, orc, halfling, gnome, goliath, dragonborn, tiefling, and aasimar in the '24 PHB, along with all the various lineage options included within those species. At the end of the day, there is a limit to what they can fit into the book.
I think goblins, by themselves, might be able to fit in under that limit, but probably not goblinoids as a whole.
