There have been a number of Helvetica variations created, including a number of language variants (Cyrillic, Korean, Hindi, Japanese, Vietnamese, and Greek among them). Others variations include:
Helvetica Light was designed at Stempel by artistic director Erich Schultz-Anker and Arthur Ritzel.
Helvetica Compressed was designed by Matthew Carter that’s similar to Helvetica Inserat, but with a few differences.
Helvetica Textbook is an alternate design with a few different characters.
Helvetica Rounded was developed in 1978 and includes rounded stroke terminators. It’s only available in bold and black versions (including condensed and obliques), plus an outline version that wasn’t available digitally.
Neue Helvetica was developed in 1983 and has more structurally unified heights and widths among its characters. It also has improved legibility, increased spacing in numbers, and heavier punctuation marks.