Wiki - List of observed Hybrids without iNat taxa

Ruddy Shelduck x Common Shelduck: https://www.inaturalist.org/observations/50705454
Wood Duck x White-cheeked Pintail: https://www.inaturalist.org/observations/105262787
Wood Duck x Northern Pintail: https://www.inaturalist.org/observations/101653605, https://www.inaturalist.org/observations/30434828, https://www.inaturalist.org/observations/30434680
Baikal Teal x Green-winged Teal: https://www.inaturalist.org/observations/106026524
African Black Duck x Mallard: https://www.inaturalist.org/observations/26683725
Ferruginous Duck x Mallard: https://www.inaturalist.org/observations/70669415, https://www.inaturalist.org/observations/70669417, https://www.inaturalist.org/observations/70669416
Mallard x Rosy-billed Pochard: https://www.inaturalist.org/observations/66193454

No problem! I'm so glad that this project exists. Thank you for taking the time to compile these!

The parentage of the "Muscovy x Wood Duck" seems extremely uncertain at the moment

Ruddy Shelduck x Mallard has been added! https://www.inaturalist.org/taxa/1364384-Anas-platyrhynchos---Tadorna-ferruginea

Wood Duck x Common Shelduck: https://www.inaturalist.org/observations/64864725

Red-crested x Rosy-billed Pochard: https://www.inaturalist.org/observations/27151381

I disagree that they don't require iNat taxa but this is your project so no need to add them if you don't want to. However Common Shelduck x Common Eider likely occur in the wild. Many of the examples I linked in the comments of the observation above are of unknown provenance.

Taiwan X Chinese Hwamei (probably worth going through all records of Hwameis in Taiwan to see which are hybrids)

Gray Heron x Purple/Black-headed Heron https://www.inaturalist.org/observations/104692653

Yellow-crowned X Black-crowned Night-Heron (https://ebird.org/checklist/S88572286)

White-faced x Black-bellied Whistling-Duck: https://www.inaturalist.org/observations/92034044

Chinese x Taiwanese Hwamei is an option available on eBird and supposedly make up a sizeable portion of the Hwamei on Taiwan (but I haven't checked for any observations on iNat)
Red-billed x Taiwanese Blue Magpie, not sure how common it is given the population of Red-billed Blue Magpie on Taiwan is very small and local, but hybrid young have been discovered there before in 2007

Thanks to everyone (esp. @liliumtbn) in searching for observations that fit for the project, and @birdwhisperer for adding them!

@liliumtbn Out of the list above, I've added only the hybrids that appear as options on eBird, except for Northern Flicker X Gilded Flicker because we're trying to figure out if near-species level taxon should be represented in hybrid taxa (ex. Townsend's Warbler x Yellow-rumped Warbler; YRWA was once considered two species and all hybrids between Townsend's is going to be with Audubon's Warblers. Should we lose that recognition just because it's lumped with Myrtle Warbler?).

eBird recognizes Tufted hybridization with both scaup species and I can add both. Imo, the linked hybrid above gives me more Lesser Scaup vibes, but who knows if the community would agree.

Here it is:

https://www.inaturalist.org/taxa/1390548-Anas-diazi---fulvigula

I also added Black-chinned x Calliope a while back but I forgot to link to here.

https://www.inaturalist.org/taxa/1373491-Archilochus-alexandri---Selasphorus-calliope

Red-crested Pochard x Common Pochard https://www.inaturalist.org/observations/119203155
@birdwhisperer This combination is on eBird if you get the chance to add it

@liliumtbn Somebody beat me to it. Hybrid taxon was added today by a different user.

https://www.inaturalist.org/taxa/1394317-Netta-rufina---Aythya-ferina

Ty!

Very interesting, just added my 2 cents

@cgbc I'd hardly call it a "known" hybrid since eBird added Song x Lincoln's in the 2021 update in response to the aforementioned checklist. A quick google search shows that this combo only occurs once in literature and that was a 2003 report, which specifically stated this is first ever recorded combo between the two. They probably occur more often than we think but identification of hybrids is probably pretty tricky.

https://bcbirds.files.wordpress.com/2016/08/bcbirds_v13_p10_apparent-hybrid-lincolns-x-song-sparrow-at-boundary-lake.pdf

Lesser White-fronted x Canada Goose: https://www.inaturalist.org/observations/40516252

Greater White-fronted x Graylag Goose: https://www.inaturalist.org/observations/10249638

Common Shelduck x Wood Duck: https://www.inaturalist.org/observations/64864725 which is an option on eBird

Eurasian Wigeon x Northern Shoveler: https://www.inaturalist.org/observations/144685000

Eastern x Black Phoebe https://www.inaturalist.org/flags/613889

https://www.inaturalist.org/observations/31690920
Snow x Bar-headed x Swan Goose (Anser caerulescens x indicus x cygnoides)

I also doubt it will be implemented but it fits the criteria for this project

Lanius collurio and Lanius phoenicuroides
https://www.inaturalist.org/flags/619284

probable BCNH x YCNH, since that still hasn't been added yet it looks like
https://www.inaturalist.org/observations/133649659

Common Eider x Mallard https://www.inaturalist.org/observations/139099508 See comments for reasoning. There's a very well known individual here and despite the poor photo this appears to be it, albeit in messier plumage due to the time of year. COEI x MALL is an option on eBird. This individual hybrid at the Seahouses is also posted a lot by photographers on Twitter

Added Mallard x Common Eider https://www.inaturalist.org/taxa/1510272-Anas-platyrhynchos---Somateria-mollissima

European Green Toad x Common Toad:
https://www.inaturalist.org/observations/197247176

@neontetraploid https://www.inaturalist.org/taxa/1536779-Nannopterum-auritum---brasilianum

Asp viper x Lataste's viper
https://www.inaturalist.org/observations/182043045

Added, and @birdwhisperer has already added the dove hybrid taxon since.