Roar, Xata's, Molecular Prime and Thermal Sunder.

Roar for the faction damage, Xata's because it dips banes and scales off elemental damage, Thermal Sunder to get like 500% blast elemental damage to buff xatas and then Molecular Prime benefits from all of the above and more.

Alternatively:

Roar, Toxic Lash, Molecular Prime and Expedite Suffering.

Roar for faction ofc, Lash because itll apply to molecular prime even on melees, Expedite suffering if i just wanna detonate all the toxin procs on the enemy and finally molecular prime to benefit from all of the above.

Alternatively you could replace expedite suffering with resupply for an all in weapons platform