Are any descriptions of Rudra's aspect ? If yes, where we can find them?
Read the shivopasana mantra of the Krishna yajurveda Mahanarayanaya Upanishad. It describes and covers the 5 primary aspects of shiva/rudra.
Rudra/Shiva is of 5 aspects sadyojata, ghora/aghora, vamadeva, tatpurusha, ishaana.
Sadyojata: source of all existence Vamadeva: the most beautiful and effulgent Aghora/Ghora: terrifying and non terrifying tatpurusha: the Supreme Personality/Purusha Ishaana: the supreme ruler and creator of all beings
His specific form is described as the following: namo hiraNya-baahave hiraNya-varNaaya hiraNya-ruupaya hiraNya-pataye ambikaapataya umaa-pataye pashu pataye namo namah
Namaha to the One who has golden hands ( hiraNya-baahave ) ; who is the golden hue or whose speech is charming ( varNa means colour or word ) ; who is of golden form ( ruupa ) or whose form is charming ; who is Lord ( pataye ) of wealth and gold ; who is the Lord of Mother Ambika and Lord of Uma and who is the Lord of all beings ( pashu : animals )
And from the rudram he is described as the following: om namaste astu bhagavan visvesvaraya mahadevaya
tryambakaya tripurantakaya trikalagni-kalaya
kalagnirudraya neelakanthaya mrutyunjayaya
sarveshvaraya sadashivaya shrimanmahadevaya namah
Om. Oh, Bhagavan, may this salutation be unto you who is the Lord of the universe, the great God, the three-eyed, the destroyer of demon Tripura, who is the Sandya time when three fires are lit, the Rudra that is the fire that consumes the universe, the blue-necked, the conqueror of death, the Lord of all, the ever-auspicious one. Salutations unto the glorious great Lord.
Hope above helps sources are Shivopasana Mantra from Krishna Yajurveda and Sri Rudram.