Kaushika grihya sutra is the only sutra followed by Atharvavedins for Srauta and smarta rites. Beside Kaushika grihya sutra two more grihya sutra belongs to Atharva veda , namely
1) Paithinasa Grihya sutra
2) Agastya Grihya sutra
The evidence for there existence is traced in Karmapanjika ( of Paithinasa Grihya sutra), Prapancha-Hridaya ( of Agastya Grihya sutra ) .
1) Paithinasa Grihya Sutra:
Compiler of Karmapanjika Srī Dhara quotes some sutras from paithinasa grihya sutra and States that the base for karmapanjika is paithinasa sutra of Paipalada shakha belonging to Atharvan veda.This means that till the time Srī dhara, paithinas sutra existed and Utkal bramhans (Orrisan bramhans ) were follower of this sutra , but with influence of time and dominating Yajurvedic schools ( Kanwa shakha of yajur veda ), this sutra got lost in darkness of time.
( My critic of Yajurvedic influence is true ,most of paipaladins have given up Atharvan shakha and are learning Kanwa shakha due to more opportunities of income from yajan-yAjan ).
But due to some dedicated Atharvan bramhans we posses” Karmapanjika “a paddhati grantha based on Paithinasa sutra.Yet in small number but, some atharvans are till the date studying Paipalada shakha and performs all rites and rituals by the help of Karmapanjika.
Due to unavailability of date of Srī Dhara swamin we are unable to trace the date till which our sutra existed.
2) Agastya Grihya Sutra:
Prapancha- Hridya describes an another grihya sutra ( in quite pseudo manner belonging to atharvan veda paipplada shakha in it’s ShAdanga Prakrana)
I’m unable to trace the author of the treatise Prapancha- Hridaya ,but after studying it
critically it is clear that this grantha was compiled after the time of Bhatta Kumarila and Prabhakar .( i.e. after 7 th century )
According to description in this treatise ,Agastya muni compiled Agastya Grihya Sutra , which was having 7 chapter . It belongs to Paippalada shakha of Atharva veda. Even in it’s veda prakrana it describes a bramhana ( not gopatha bramhana ) with 8 chapters affiliated to Paippalada shakha .
So these are few traces of this lost sutras.It is quite interesting to see that, both of these sutras belongs to Paipalada shakha . I think like kaushika sutra ( 4 shakhas of atharva veda follow it namely Shaunak,Bramhavada,Jalad,JAjal ) it is probability that some other lost shakhas also follow this two sutras.