foreach (var item in downloadedPipelines)
{
    if (!staticBranches.Contains(item.Ref))
        updatedPipelines.Add(new Pipeline { Id = item.Id, Ref = item.Ref, Sha = item.Sha, Status = item.Status });
    //Arbitrary pipelines count
    if (updatedPipelines.Count >= 10)
        break;
}

to to samo co

updatedPipelines = downloadedPipelines
	.Where(item => !staticBranches.Contains(item.Ref))
	.Select(new Pipeline { Id = item.Id, Ref = item.Ref, Sha = item.Sha, Status = item.Status })
	.Take(10)