What are these tags?

Can someone tell me what these tags are and their use?

Here is a list of supported standard fields:

There I see only ENCODERSETTINGS whch is probably written by the encoder.
All other tag fields that you found are user-defined fields - so the are probably only of limited interest as most players cannot cope with user-defined fields.
These fields proabyl make only sense in the context of the program that has written them.

seems to belong to the MP4/Quicktime FTYP tag, according to
isom MP4 Base Media v1 [IS0 14496-12:2003]
iso2 MP4 Base Media v2 [ISO 14496-12:2005]

Please read the linked note #1:

a) All ftyp's may be used as "major" or "compatible" brands, except as noted in [5] and [6] below.
b) ftyp's may be case sensitive. Recent editions this table have been updated to reflect the defined or common usage, but apps which read ftyps would be well advised to read them in a case insensitive fashion.
c) All ftyp's must contain 4 characters. If three characters are shown in the table, a trailing blank (i.e. a space character; ASCII 0x20) is implied. Similarly, if only two characters are shown, two trailing blanks are implied. For example, "qt" is really "qt " - note the two trailing spaces.

[5] 'isom' is seen used as a major brand, though it is currently prohibited by ISO/IEC 14496-12 sec 6.3 paragraph 2.

[6] Like 'isom', use of 'iso2' as a major brand is specifically prohibited by ISO/IEC 14496-12 sec 6.3 paragraph 2.

Do you think if I remove these fields it would harm my files?

Added metadata usually follows a special purpose that should be of benefit for the user.
Do you, as the user, have any benefit from these fields?
If yes: leave them as they are.
If not, then remove them.
(I do not see any benefit from them. But I am not relevant right now.)

Well I don't know if I benefit from these fields. I just use these mp3 files to play music.. I don't see any other use.

You could use a copy of a file in which you delete the fields and then see whether there are any technical drawbacks (which I doubt). If there are not - then delete them if you are bothered by them.

The tags should only provide information, and not affect the audio of the file. The only exception is the replaygain tags, which could affect volume of the playback IF your media player supports this.

I'm sure, you can remove THIS fields without harming your files.
(But as always for actions that remove or change metadata: A backup is recommended...)

The only (known) metadata tags with a direct influence to the audio part are the replay gain tags, as @MotleyG already explained.

Your songs will be played even without any metadata. But if you delete all of your tags completely, you can not sort anymore by artist, title, album, year for example.

If you are still afraid of messing the files then just duplicate all of those fields with adding the their names something like BACKUP and copy that data to them - and then wipe clean the original fields. And then just use those files

I am sure that in a couple of months you will simply forget that such fields / data were even there in a first place