No brand did ever an Allen's swamp monkey.
There are various mantled guereza: Action Products, K & M, Kaiyodo, Play Visions, and Starlux. I think the Kaiyodo model is the best:
P1170944 — Postimage.org (here, to the right, with the Action Products one). No brand did any other species of colobus.
Swans are very popular amongst figurine makers. Of course, most are mute swans or black swans. The latter is done by Papo, Safari LTD, Science and Nature, and Yowies. The Yowies black swan is too short-necked. The Papo and Safari swans have spread wings, Papo have the best sculpt, but wrong colours (wings completely black and bill completely red) while Safari have correct colours but not so perfect sculpt (and a knob at the base of the bill as if it were a mute swan). The Science and Nature black swan is maybe the best one, tough not perfect:
https://images-na.ssl-images-amazon.com/images/I/41ZkW4k3w+L.jpg
Mute swan is heavily represented with no less than 9 brands and 18 models representing the species. The brands are Bullyland (five models, only one of them enough realistic, that is one with chicks), CollectA (perfect model), Maia & Borges (perfect model), Mojo fun (perfect model), Nayab (not very good model), Papo (perfect model with spread wings), Playmobil (two models: adult and cygnet. You know what Playmobil is... they don't try to be super realistic), Safari LTD (a model with spread wings and poseable neck, not perfect quality), and Schleich (six models, all of them relatively good except the Mini version that looks like a very simplistic coscoroba swan much more than a mute swan. And the adult with cygnets is not very convincing. too short neck, too "duckish" face and bill. The other three adults are fine, and the sixth model is a row of 4 cygnets on a green platform)
Finally, whooper swan has been done by two brands that are, of course, Japanese brands. One is the Eikoh (not bad sculpt, but wrong bill colour) and the other is Kaiyodo. Like almost all Kaiyodo figures, it must be assembled. Kayiodo did two models: one standing
https://s.ecrater.com/stores/355123/55fa898081bb8_355123b.jpg and one swimming that I think it a more poor sculpture
https://i.ebayimg.com/images/g/500AAOSw8W1bfYwy/s-l640.jpg
Some hornbills has been made into figurine. Brands paid attention only to larger species, as would be expectable. So we have Great Indian Hornbill done by Albert Heijn, Bandai, Bullyland, Furuta Chocoegg and Yowies. The Furuta one is the best:
https://www.picclickimg.com/d/l400/...yodo-Furuta-Choco-Egg-Great-Hornbill-Bird.jpg
Southern Ground Hornbill has been made by Yowies USA and is not bad:
https://www.picclickimg.com/d/l400/...-Brand-Collectible-Figure-Southern-Ground.jpg
By last, Rufous hornbill has been made by Nayab. A very poor painting, tough.
http://toyanimal.info//images/thumb/f/f0/Hornbill.JPG/800px-Hornbill.JPG Some collectors repainted it into a Palawan hornbill:
https://i.servimg.com/u/f58/16/10/21/19/dscf2161.jpg
Gelada has never been made into figurine by any brand. There are some non-toy and extremely expensive figurines of it such as this one from Signatustudio:
http://www.signatustudio.com/uploads/2/5/6/9/25691557/p7190026_orig.jpg it cost 50 € at their website...