Yay, someone did some work for me.
I'm going to constantly edit this post as I find the reasons for these, so keep checking.
All 4 of these are the result of the Wonder Card/partial card data being synchronized with their indices in the save file. This is fine.
Edit: The same is true of the Platinum offsets.
Edit 2:
9F42-AD0E are the same as the Diamond/Pearl/Platinum changes.
The others are Pokedex language flags, in this case, being set from nothing to English. My data says that HG/SS, unlike Diamond/Pearl/Platinum, set the data to the native language of the game when a Pokemon is seen. So if yours were zero before, either my data is wrong, or this was edited by something else.
Edit 3:
0x1C800-0x1D297 is the Mystery Gift block. The block is encrypted with a partially random value by the game, so PokeGen does the same each time you save. This is the reason for all the data being changed.
0x40800-0x41297 is the copy of the Mystery Gift block in the backup half of the save data.
Edit 4:
I did some testing and discovered that I was misinterpreting the information I had. HG/SS also sets the byte to 0 when a Pokemon is first seen, so those shouldn't have been flagged with 2 (English). It doesn't hurt anything, but it'll be fixed.