There are only two classes of enlightened beings that attained
Fruition without the aid of Buddha's teachings.
1) Buddha -- all Buddhas attain the perfect enlightenment
(Annutarasamyaksambodhi) by themselves without relying on any other
teachers, in that lifetime.
2) Pratyekabuddhas -- all Pratyekabuddhas attain enlightenment by
themselves by seeing into the truth of Interdependent Origination
by looking at various signs like falling leaves, and so on.
Even so, these beings have practised many many lifetimes before,
under enlightened teachers and the Buddhas. For a Buddha, he has to
practise a lot of lifetimes before as a Bodhisattva, perfecting the
10 paramitas, before attaining Buddhahood.
For a Pratyekabuddha, he has practised many lifetimes under other
enlightened teachers as well, but it just so happen that at that
lifetime he attains awakening, there were no dharma teachings.. but
his high capacity and wisdom allows him to penetrate into the truth
of reality.
For most of us we need to deligently learn and practise the dharma
of Shakyamuni Buddha. Practitioners of the self-liberation vehicle
aims to attain Arhatship. Practitioners of Mahayana not only aims
to attain liberation, but also practise the Bodhisattva path, have
vows of great compassion for all sentient beings, perfect the
paramitas, and so on.