Nancy and Jim, the original founders of the gardening club, need more volunteers. One pair of gardening shears has been missing from the gardening shed since last year.
In the first sentence Nancy and Jim are the subjects of the sentence. The verb is need. Need agrees with the plural subject Nancy and Jim. Sometimes it helps to substitute they for a plural subject when you double check. "They need" is correct.
In the second sentence One is the subject. One is a singular subject. The verb phrase is "has been missing". One has is correct subject verb agreement.
The other sentences are all wrong: club-require, town-have, gardening-have. They should be changed to club-requires, town-has, gardening-has.