Hunter x Hunter (2011), Terra Formars Recommendations
Both contain battles with meta-morphed life forms. Both interweave deaths with superb storytelling and awesome fights. There is a certain 'feel' that you can get in the last arc of hunterxhunter 2011 that you also get in the second half of Terra Formars which is perhaps due to their similar use of narrators.
The Chimera Ant Arc of HxH has numerous similarities with TerraFormars; seemingly non-threatening bugs are sent to an abandoned region, but over time they become a major threat that must be stopped. The bugs develop humanoid features and even form an empire, U-NASA/Hunter's Association send a unit of humans to prevent the threat from growing larger.
The intense atmosphere, despair, and levels of gore are very similar in the two, basing the powers on real life animals is done for both the Chimera and members of BUGS2.
Both have a huge cast with diverse characters and the main protagonist is not always the center of all what happens.
Both have complex battles and situations and a lot of plot twist, though Terra Formars is a lot more fast-paced so I think it's a bit less enjoyable because I have the feeling that everything is always changing; also Terra Formars' dire situations are resolved with pure strenght more often.
In both anime there are enemies which are anthropomorfic insects.
Both have a lot of dialogue and also an external narrator that explains a lot of what's going on.
OSTs and drawings/animations are good in both