user25249: Most open source chess engines with hand-tuned evaluations are known for their innovations on search (Fruit, Stockfish).
I was inspired by HIARCS' generally more human-like play and the fact that neural network based engines like Leela suggest that we have more work to do when it comes to evaluation functions.
The reason is that I'd like to apply the same evaluation functions in a chess engine that I'm working on.
Which open source engines are out there are known for its deep positional understanding? Unfortunately, engines known for their positional understanding such as Shredder, HIARCS, and Komodo are closed source.

user24511: Stockfish 12 is objectively the best in the free engines that is publicly accessible.
Estimated Elo ~ 3230. There is another engine mildly more powerful however I don't believe its available and the difference is negligible. Stockfish has good positional awareness, aggression etc can be tampered with for interesting outcomes.
I look at Komodo Dragon as a strong closed source engine and the Armageddon feature where it treats draws as a loss is extremely good especially for training purposes.
Reality of it is almost all engines out perform human players in positional awareness , tactical and strategic play. Its like comparing brands of paracetamol. All the same and any differences are so minute we'd never notice them.

user25282: A really strong and great positional open source engine I have used is Rodent.  The last version was Rodent IV and is available at http://www.pkoziol.cal24.pl/rodent/rodent.htm
Of course Chess Programming wiki continues to be a good place to research and discover engines and the following link shows only open source engines.
https://www.chessprogramming.org/Category:Open_Source

25249: <p>Most open source chess engines with hand-tuned evaluations are known for their innovations on search (Fruit, Stockfish).</p>
<p>I was inspired by HIARCS' generally more human-like play and the fact that neural network based engines like Leela suggest that we have more work to do when it comes to evaluation functions.</p>
<p>The reason is that I'd like to apply the same evaluation functions in a chess engine that I'm working on.</p>
<p>Which open source engines are out there are known for its deep positional understanding? Unfortunately, engines known for their positional understanding such as Shredder, HIARCS, and Komodo are closed source.</p>
 24511: <p>Stockfish 12 is objectively the best in the free engines that is publicly accessible.
Estimated Elo ~ 3230. There is another engine mildly more powerful however I don't believe its available and the difference is negligible. Stockfish has good positional awareness, aggression etc can be tampered with for interesting outcomes.</p>
<p>I look at Komodo Dragon as a strong closed source engine and the Armageddon feature where it treats draws as a loss is extremely good especially for training purposes.</p>
<p>Reality of it is almost all engines out perform human players in positional awareness , tactical and strategic play. Its like comparing brands of paracetamol. All the same and any differences are so minute we'd never notice them.</p>
 25282: <p>A really strong and great positional open source engine I have used is Rodent.  The last version was Rodent IV and is available at <a href="http://www.pkoziol.cal24.pl/rodent/rodent.htm" rel="nofollow noreferrer">http://www.pkoziol.cal24.pl/rodent/rodent.htm</a></p>
<p>Of course Chess Programming wiki continues to be a good place to research and discover engines and the following link shows only open source engines.</p>
<p><a href="https://www.chessprogramming.org/Category:Open_Source" rel="nofollow noreferrer">https://www.chessprogramming.org/Category:Open_Source</a></p>
