Are there Sanghas(in the more broad meaning of the word) of those who practice like monks but aren't officially monks and have not been ordained as monks by monks? If they could call themselves "Bunks" or something besides "monks", would this be problematic? Are there any scriptures related to this?
In the Mn140 Pukkusati is referred to as a Bhikkhu before receiving the going forth;
Ven. Pukkusati also spent most of the night sitting [in meditation]. The thought occurred to the Blessed One, "How inspiring is the way this clansman behaves! What if I were to question him?" So he said to Ven. Pukkusati, "Out of dedication to whom, monk, have you gone forth? Who is your teacher? Of whose Dhamma do you approve?"
There aren't any actively recruiting communities that i know of atm.
Also Anagarikas are basically not ordained and are in training.
‘The Saṅgha of the Buddha’s disciples is practicing the way that’s good, straightforward, methodical, and proper. It consists of the four pairs, the eight individuals.
The four pairs (and eight individuals) are defined indirectly in the same sutta:
The stream-enterer and the one practicing to realize the fruit of stream-entry. The once-returner and the one practicing to realize the fruit of once-return. The non-returner and the one practicing to realize the fruit of non-return. The perfected one, and the one practicing for perfection.
In the broadest sense, the Saṅgha comprises all those who have faith in the Buddha, his teachings and the Saṅgha. And their faith is strong enough that:
... a noble disciple’s ethical conduct is loved by the noble ones, unbroken, impeccable, spotless, and unmarred, liberating, praised by sensible people, not mistaken, and leading to immersion.