An updated forkcoins tree chart (only blockchains) Where can I find something conveying this information, but up to date?
digraph {
  # rankdir = LR;
  splines = polyline;

  # Bitcoin is the original chain.
  node0 [label = &quot;Bitcoin\n~15000 $ US (BTC / Nov 2020)&quot;];

  # Bitcoin Cash was a first successful fork.
  node1 [label = &quot;Bitcoin Cash\n~250 $ US (BCH / Nov 2020)&quot;, color = &quot;#333333&quot;,
         fontcolor = &quot;#333333&quot;];
  node0 -&gt; node1 [label = &quot;Aug 2017&quot;, color = &quot;#333333&quot;,
                  fontcolor = &quot;#333333&quot;];

  # Bitcoin Gold was a second try to make a successful fork.
  node2 [label = &quot;Bitcoin Gold\n~9 $ US (BTG / Nov 2020)&quot;, color = &quot;#999999&quot;,
         fontcolor = &quot;#999999&quot;];
  node0 -&gt; node2 [label = &quot;Oct 2017&quot;, color = &quot;#999999&quot;,
                  fontcolor = &quot;#999999&quot;];

  # Subsequent forks were tried, but most have been low valued.
  node3 [label = &quot;Bitcoin Diamond\n~.5 $ US (BCD / Nov 2020)&quot;,
         color = &quot;#bbbbbb&quot;, fontcolor = &quot;#bbbbbb&quot;];
  node0 -&gt; node3 [label = &quot;Nov 2017&quot;, color = &quot;#bbbbbb&quot;,
                  fontcolor = &quot;#bbbbbb&quot;];
  node4 [label = &quot;United Bitcoin\n~.6 $ US (UBTC / Nov 2020)&quot;,
         color = &quot;#bbbbbb&quot;, fontcolor = &quot;#bbbbbb&quot;];
  node0 -&gt; node4 [label = &quot;Dec 2017&quot;, color = &quot;#bbbbbb&quot;,
                  fontcolor = &quot;#bbbbbb&quot;];

  #   There were more forks in Dec 2017 but I think they're all low valued.
  # Ignoring Bitcoin X, Super Bitcoin, Bitcoin Hot.

  # Bitcoin SV was forked from Bitcoin Cash.
  node5 [label = &quot;Bitcoin SV\n~150 $ US (BSV / Nov 2020)&quot;, color = &quot;#666666&quot;,
         fontcolor = &quot;#666666&quot;];
  node1 -&gt; node5 [label = &quot;Nov 2018&quot;, color = &quot;#666666&quot;,
                  fontcolor = &quot;#666666&quot;];

  #   There was a second Bitcoin Cash fork (Node / ABC) but it seems that Node
  # got almost all of the hashing power and ABC is not an exchanged token right
  # now, if ever.
  # node6 [label = &quot;?&quot;];
  # node1 -&gt; node6 [label = &quot;Nov 2020?&quot;];
}


Please note this aims discussion on the forks of the original Bitcoin blockchain (forkcoins, specifically), not discussing the codebase forks bootstrapping a different blockchain.
As far as I'm aware, the newest graph mapping forkcoins which spun off from Bitcoin is Bitcoin Magazine's Map of Bitcoin forks infographic. It was published in April 2019, so it will not include newer forks like the upcoming BCH split. It does include the major project forks, but doesn't list all forks (there have been over 40 mostly irrelevant forkcoins).
I looked up a prior project called Map of Coins which was aiming to collect the full pedigree of altcoins that forked from Bitcoin's codebase (and other original projects) but it appears to not have gotten updated since 2017.