You can find the full collection of these collaborations on streaming platforms like Spotify and Apple Music. AMNEZIA - song and lyrics by Bobo Armani, SST ... - Spotify
: Features Bobo Armani, Nika (Niki Kotich), Kickdown, SST , and Pameca. bobo_armani_x_niki_kotich_x_pameca_x_kickdown_x...
The series of artists you mentioned——primarily collaborated on the 2022 album titled ЧЕРЕН ПЕТЪК (Black Friday). These artists are prominent figures in the Bulgarian trap and hip-hop scene, often associated with the Murda Boyz collective. You can find the full collection of these
The "long piece" likely refers to one of their major collaborative tracks or the album itself, which features several high-energy songs with multiple contributors: Nika (Niki Kotich)