In this video, Adnan Ibrahim argues against Ijma'. He also quotes Imam Ahmed:
"قال " من ادَّعى الإجماع فقد كذب ، وما يدريه لعل الناس اختلفوا
Imam Ahmed said: "The one calling upon ijma' has lied!"
The same quote is found here, more context of it:
والإجماع إجماعان ، إجماع ظني وإجماع قطعي ، والأول هو الذي يثبت بالبحث والتحري عن أقوال الأئمة ، ويحتاج من مثبته إلى استقراء لكتب الخلاف ، وهو الذي أنكره الإمام أحمد وقال " من ادَّعى الإجماع فقد كذب ، وما يدريه لعل الناس اختلفوا " .
In this video, he denies ijma' to be a part of his methods of usul al fiqh.
Which sunni scholars denied ijma' as a method among the methods in usul al fiqh?
This question is of course based on another question, did any sunni scholars really deny ijma?
Disclaimer: I am not supposing these quotes are proofs too deny ijma', rather it seems some have used them when aruging against ijma'. I know they are possible to be interpreted in another way in its context. Also, it seems to be different interpretations of what exactly is ijma'. And the person denying ijma' isn't necessary denying the matters as five prayers a day and such.