here's all the open flags on Opuntia, but I think we need clarity at the genus level here before knowing how to address them:

https://www.inaturalist.org/flags/485634 - Opuntia covillei - this is listed as a synonym of Opuntia x vaseyi on Plants of the World. Not a taxonomy person, but hopefully some experts can help sort this out.

https://www.inaturalist.org/flags/488626 - Opuntia stricta - Opuntia tehuantepecana no es sinonimo de Opuntia stricta, O. tehuantepecana es una especie aceptada

https://www.inaturalist.org/flags/361001 - Opuntia rzedowskii - Synonym of O. lasiacantha Pfeiff.

https://www.inaturalist.org/flags/495838 - Opuntia azurea aureispina - this subspecies is also listed, with observations, as full species O. aureispina. One of the names has to be deleted

https://www.inaturalist.org/flags/508294 - Opuntia galapageia - Opuntia echios varieties still grafted here

https://www.inaturalist.org/flags/232990 - Opuntia humifusa - common name issue - see comments

https://www.inaturalist.org/flags/510351 - Opuntia leptocarpa - distinct from O. macrorhiza?

https://www.inaturalist.org/flags/323878 - Opuntia mojavensis - it's a synonym of Opuntia phaeacantha: http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:136823-1

https://www.inaturalist.org/flags/302170 - Opuntia polyacantha - Got another variety for you - var. schweriniana is missing. Synonym is heacockiae

https://www.inaturalist.org/flags/282956 - Opuntia x - suggestion

https://www.inaturalist.org/flags/345514 - Opuntia cymochila - this is not a synonym of O. tortispina, they are very different entitites, and should not be lumped.

https://www.inaturalist.org/flags/328667 - Opuntia olmeca - Opuntia olmeca es un nombre no valido, el nombre valido es Opuntia tehuacana, todas las fotos pertenecen al nombre de O. tehuacana, yo estoy realizando una tesis de Doctorado sobre esta especie, saludos

https://www.inaturalist.org/flags/328913 - Opuntia acaulis - synonym of Consolea acaulis in POWO

https://www.inaturalist.org/flags/328914 - Opuntia × - hybrid without an epithet; probably needs community discussion and addition to the curator guide if this is going to be an accepted taxon on iNat

https://www.inaturalist.org/flags/304193 - Opuntia discata - it is listed as a synonym of Opuntia engelmannii in POWO and should be lumped in or perhaps revised as a var to maintain the site's standards

https://www.inaturalist.org/flags/336604 - Opuntia vaseyi - O. vaseyi is a valid species taxon, and the hybrid designation is unsupported and incorrect.

https://www.inaturalist.org/flags/352649 - Opuntia × occidentalis - This should not be listed as a hybrid. This "hybrid" status is based on pure supposition with no science to support it. This was originally described as a good species.

https://www.inaturalist.org/flags/328653 - Opuntia macrarthra - synonym of Opuntia mesacantha subsp. lata (Small) Majure in POWO

https://www.inaturalist.org/flags/405393 - Opuntia macrorhiza pottsii - I don't know if it can be fixed. The taxon swap was to species Opuntia pottsii, but taxon ID number for Opuntia macrorhiza is apparently there instead. The output from the swap seems to be confused now. I don't know how to fix it - if it can be?

https://www.inaturalist.org/flags/460591 - Opuntia gilvescens - it should be merged with Opuntia phaecantha, per POWO: http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:175105-2

I have to admit that the taxonomy of the genus Opuntia is still quite a mess (& that comes from an opuntioid taxonomist). I have worked on this genus for many years in my region, after finishing up Cylindropuntia for my dissertation, and I think the genus Opuntia might just kill me! There are definitely still undescribed species in our region and I tend to take a very conservative (lumping) approach to the genus in Baja Ca and southern CA. I have definitely seen some others that tend to split the genus a lot, but I have not been able to make sense of many of those names from a biogeographical or evolutionary perspective. The short answer is that we still do not have all of the taxonomic answers in regards to this genus (at least in my region) and many nomenclatural treatments are just not very accurate. I would suggest being as liberal as possible with the names and not following just one taxonomic guide at this point until the genus gets worked out a bit better. Where are all of the grad students that should be working on this taxonomic problem??