I also created a list on mdl with this info and more, it is here.

A large gap of time in the Lost Tomb world (~8-9yrs from Ultimate Note). Hence why Wu Xie looks older and has really been through it.

  • Tomb of the Sea: After all these years, Wu Xie is hardened by the grave-robbing life and is different from his innocent self in The Lost Tomb.
  • Reunion: Sound of the Providence: Wu Xie has finally retired from grave robbing until he gets a text message from his missing uncle entangling him in another mystery.
  • Reunion: Sound of the Providence 2: Second season of Reunion.
  • Mystic Nine [optional]: this is a stand-alone prequel set during the 1930s. It does not include Wu Xie, Qiling, or Pangzi but involves the nine major grave robbing families (including Wu Xie's) in Changsha. It helps to watch this because it involves the family politics that is mentioned throughout the rest of the shows. 

If you want more information, there is a fandom wiki of the books the shows are based on here and the show wiki here (both contain spoilers!).

If you have any more questions, feel free to ask~

What about the Mystic Nine movie? 

Yes! There's a mystic nine movie that, last i heard, is still filming.  Don't know when it is projected to air. There's also rumored dramas about Wang Canghai and an adaptation of the book Zang Hai Hua. I will add them when we get a synopsis :D

Okay Cool Thanks @taomubiji I’m looking forward to it.

Really there is mystic nine movie hhhmmm good to hear i hope the characters is the same😊😊

Thank you so much! I was gonna watch The Lost Tomb, but then I saw the various other works that are in the series and I was confused about what order these dramas should be watched in. Thank you!

Glad I could be of some help~

Also @Neilmar, no it seems like it will be with different actors. 

I've only watched the latest Reunion the sound of providence and now the Ultimate Note and I'm loving the Ultimate Note very much ,, the story is so good and the acting is excellent also the Bromance is  heightened 

I just finished Ultimate Note and you're right, it's soo good. The highest quality dmbj adaptation so far~~ Especially Qiling's actor :D

I have watched The lost tomb 1 and 2 now. Can I watch Ultimate Note now or should I wait and watch "The Lost Tomb 2: Heavenly Palace on the Clouds" (that hasent been realesed yet) first?  If that is so, do anyone know when it will air? 

 LunaAdr:

I have watched The lost tomb 1 and 2 now. Can I watch Ultimate Note now or should I wait and watch "The Lost Tomb 2: Heavenly Palace on the Clouds" (that hasent been realesed yet) first?  If that is so, do anyone know when it will air? 

You can watch it before lost tomb 2 ,, they explain every thing in it ,, You can watch Ultimate note even if you didn't watch any previous lost tomb dramas it's self explained and also the most mentioned one in it is mystic nine drama..... it's heavily based on it mostly .. the story of the Xiao ge's origin ,,,, if you want to watch something relatable most to ultimate note 

Ok, thank you! So there wont be any spoliers or things i dont understand if I watch Ultimate note before The lost tomb 2: HPOTC then? 

 LunaAdr:

Ok, thank you! So there wont be any spoliers or things i dont understand if I watch Ultimate note before The lost tomb 2: HPOTC then? 

There were little things from Mystic nine drama but not very significant 

the drama as itself is amazing even if you didn't watch any previous seasons ,, I say give it a go 

you will like it as we all did 

It's different in so many ways than it's previous season and as the fans of the books said ,, it's the best adaptation yet to the whole series 

the friendship and Bromance is off the charts amazing 

you can search on twitter Ultimate Note ,,see for your self how fan reacted to it 

 LunaAdr:

Ok, thank you! So there wont be any spoliers or things i dont understand if I watch Ultimate note before The lost tomb 2: HPOTC then? 

You will be a little confused about some things in the first episode because they talk about something included in The Lost Tomb 2:HPC. I don't think it's such a big spoiler that it's worth waiting for that show to air, especially because the air date is still not confirmed. But it will probably air in the first half of 2021. What happens in LT2:HPC is not that important plot-wise for Ultimate Note.