I have this Black and Blue Mircro ... I have it on the Gallery and it should be in my inventory but it is not. Same with Tiny Tudor, not sure if I had that one in the gallery. I searched for it in my inventory, but not there. There are no mods or CC in the build even though I checked that option. I think a few more things are missing from my inventory .. I can see gallery if they are not being down loaded. Yet still cannot find Black and Blue Mircro in my inventory. Yes, I use my own builds. alot.
Ok, by inventory, I am assuming you are referring to your library and from what you have said, I also assume that other lots you use are still there and only those 2 are missing. I am also assuming that these are your lots that you built and saved to the library and that you do not use any cc or mods.
Houses, even when you place them in the game do not get removed from the library so the only things that I can think of are:
1 - You accidentally deleted them and didn't realize it or don't remember. I've done that, sadly, more than once.
2 - One of the files for the lots became corrupted somehow so it doesn't show up.
3 - One of the files for the lots were accidently deleted or not copied to the tray folder. Easy to do if you copy individual files from one Sims 4 tray folder to another rather than drag the tray folder from one game to another especially if you have more than one lot in the a tray folder. I have done that several times since I do all my major builds in a different game than my main save. It is easy to miss one file as sometimes they do not save right together. There may be files from other lots intermixed together in that folder. An easy way to check if you have all the files associated with a lot is build something in a new Sims 4 tray folder and save it to a clean tray folder and count the files, then look in your original tray folder and sort by date and time and count each group to make sure they have the same number of files. If one has files missing, then you've probably found the problem.
4 - Or, which is the most likely, you have a filter set that is blocking them from view. Just because a lot does not have any downloaded cc in it, sometimes they won't show up unless you check the cc box as the game, library and gallery do treat some custom things, like paintings your sims create, for instance, as cc even though they really aren't. So you might want to check again trying all the filters just in case. I know you said you tried with the cc filter checked but it can't hurt to try again. And while you're at it, try all the other filters too. Sometimes, things that are there don't show unless the right combination of filters are checked.
And lastly, if you do use any mods and cc, lots will not show without the cc filter if they were created in a game that does have it even it you used none on a lot. I have that happen. Just the presence of some things in the mods folder, even it never used will cause a lot or sims to be flagged as cc even after those mods and cc have been removed from the game. I also have a couple of mods that always cause my sims or lots to be flagged as cc when I save them to my library. Don't know why, but they do.
Hope this helps you find your missing lots.