Gambling? Killing spree? Have you done those ?
set up a house get all weapon mods or use fiends as test subjects for weapons
1. Collect every pencil in the game.
2. Play a character where you max out Speech/Survival/Barter/Medicine before you even start to work on any other skills.
3. Blow yourself up 1,000 times.
4. Kill someone at Mojave Outpost and carry their body to Ellis Air Force Base without fast traveling. If you drop it, you have to start over.
5. Play the game all the way through using only pistols.
6. Play the game all the way through using only the Baseball Bat.
7. Go outside for a bit and walk around.
I have completed the game 100% many times, and on thing ive done is gotten all of the unique weapons and armours in the game, including the add ons. it requires a lot of quests, and certain skills... but they're badass items so... its fun and worth it.