So I never really played these Fallout games that much in my experience. Only Fallout 3 on my Xbox 360 back in the day. Never fully played New Vegas.

So my question is on the DLCs they have its this. Which DLC;/Expansion is similer to these kinds of DLC/Expansion that the Elder Scrolls games had.

Specifically Bloodmoon for Morrowind, Shivering Isles for Oblivion, and Dragonborn for Skyrim,

What these 3 Expansion/DLC have in common is that they offer a completely whole new open world continent. Bloodmoon had the Island of Solstheim filled with a whole new monsters and dungeons, and its own main story quest. Shivering Isles has the eponymous Daedric Realm, and Dragonborn is Solstheim again but radically changed from Bloodmoon's version.

What DLC/Expansion in Fallout 3 and New Vegas is similar to these DLCs I mentioned?

For Fallout 3 all of the (except for Broken Steel) add completely new areas. Point Lookout being the best of them IMO. Broken Steel extends the story past the original ending.

For New Vegas all bar the Gun Runners Arsenal add new areas. The highlight being Old World Blues. Know that across all of them there is a secondary story being told about the Courier and another character.

GRA adds weapons and challenges but no areas of significant content

All add new areas yes, but what I am looking for is more like a whole new open world.

From what I have seen of Fallout 3, I don't consider Operation: Anchorage and the Pit the same thing as say a Shivering Isles.

Operation: Anchorage is more like one big giant Dungeon.

And The Pit I consider to be more akin to Morrowind's Tribunal which took place only in a city and not a new landmass.

Point Lookout however does seem to be the kind of expansion I am talking about. Where its practically like half a whole new game.

You wan't more areas to see then add mods.

The maps are fairly big as is what with the copy paste nature of it.

Well there is that New California mod for New Vegas.

No Tribunal?

Massive sized mods (which have been finished) that add a new map and landmass are very rare. Lots of good ideas and not even half baked attempts given up to rot on the nexus.

Here is one (Alton IL) for FO3 that made it though: https://www.nexusmods.com/fallout3/mods/16949?tab=description

I don't think we could count a fistful of these though.

Many mods out there but none better than Tales of the Wastelands.

If you played Fallout 4 whats the DLCs that's like Point Lookout and Old World Blues?

Far Harbor

Fallout 3

Broken Steel is absolutely mandatory as it increases level cap to 30. Level cap 20 is absolutely nuts. Even with 30, I spent probably more than half of the game on the 30 cap. And once you stop levelling, the game started to bore me pretty quickly to the point I had to force myself to finish it.

I for one liked Operation Anchorage the most, exactly because of it being more linear. I was pretty bored with the huge open world in the main game so it was a nice change of pace.

Point Lookout felt meh overall. I also found it hilarious that the hillbillies there are pretty much the tankiest enemies in the entire game.

Mothership Zeta you can safely skip.
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Fallout New Vegas

Dead Money was alright. Once again, a nice change of pace from the open world in the normal game. Pretty linear but has interesting companions.

Honest Hearts was decent. A compact open world with some interesting new characters and companions.

Old World Blues is very good and one of the funniest. Probably the most fun I had in Fallout New Vegas. Also comes with its own small open world.

Lonesome Road felt kinda meh. Some interesting plot gets explained but otherwise nothing stellar IMO.

It's probably Bethesda's best DLC ever, honestly.