The Unicode character set has characters for each of the eight trigrams at codepoints U+2630 to U+2637:
☰ ☱ ☲ ☳ ☴ ☵ ☶ ☷
The eight trigrams are:
☰ Qián (Tian1) 天 "Heaven"
☱ Duì (Ze2) 澤(泽) "Lake/Marsh"
☲ Lí (Huo3) 火 "Fire"
☳ Zhèn (Lei2) 雷 "Thunder"
☴ Xùn (Feng1) 風(风) "Wind"
☵ Kǎn (Shui3) 水 "Water"
☶ Gèn (Shan1) 山 "Mountain"
☷ Kūn (Di4) 地 "Earth"
Trigram Fonts, Trigram Character Set, I Ching Character Set.