I couldn't make it work with plain regex in SQL, but I was able to create a JavaScript UDF to get the desired results:
create or replace function find_repeated("x" string)
returns string
language javascript
as
$$
return x.match(/(.+)1/g)
$$;
select x.value
, find_repeated(x.value)
, find_repeated(x.value) is not null has_repeated
from table(split_to_table('abc,abcabc,snowsnowflake', ',')) x
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