Really like MVRV.  True Market Value is interesting as well in that it reduces the impact of 1,000,000 BTC at zero value (Satoshi’s stash) and other piles similar to that due to the duration held.  Checkonchain.com has a bunch of charts like this.  https://charts.checkonchain.com/btconchain/unrealised/mvrv_aviv_1/mvrv_aviv_1_light.html 

 The true market mean and the whole cointime economics research by  @_Checkmatey_ is really interesting