There are 130 bulbul species worldwide and 29 species which occur in Malaysia.
I only found six species so far;
1) Yellow-vented Bulbul (Pycnonotus goiavier)
2) Hairy-backed Bulbul (Tricholestes criniger)
3) Buff-vented Bulbul (Iole charlottae)
4) Black-headed Bulbul (Pycnonotus atriceps) - most colourful that I have seen.
and add this two new one;
5) Red-eyed Bulbul (Pycnonotus brunneus)
6) Streaked Bulbul (Ixox malaccensis)
Most bulbul look the same from a far - with shade of grey and brown, . I only know their species name only when downloaded the images to computer and referring to Birds Guide Books.
Red-eyed Bulbul (Pycnonotus brunneus)
Streaked Bulbul (Ixox malaccensis)