The most common and most likely answer to this crossword clue is the 8 letter word VARIANTS
I've seen this crossword clue in The Daily Telegraph
V
A
R
I
A
N
T
S
More clues leading to the result VARIANTS
Buddy explains!
The straight part
We know that "Different forms" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case different forms = variants.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VARIANTS mean?
VARIANTS noun- Something that is slightly different from a type or norm.
- A different sequence of a gene (locus).
- A variable that can hold any of various unrelated data types.
- One of a set of words or other linguistic forms that conveys the same meaning or serves the same function.