I did a case sensitive search for usages of .<MethodName>( on https://grep.app/ in C# files.
For some I removed usages that were obviously not related to Linq where the problem was obvious and common - e.g string.Join( and sb.Append(.
| METHOD | COUNT |
|---|---|
| ToArray | 83482 |
| Contains | 82583 |
| Select | 82428 |
| Where | 61423 |
| ToList | 60149 |
| Any | 48545 |
| FirstOrDefault | 44154 |
| First | 34373 |
| Count | 29782 |
| Append | 19144 |
| Concat | 17894 |
| OrderBy | 17445 |
| Single | 17061 |
| Skip | 12641 |
| SelectMany | 11054 |
| Range | 10648 |
| Take | 10254 |
| All | 9829 |
| ToDictionary | 9577 |
| Last | 9291 |
| Join | 7811 |
| Sum | 7276 |
| Reverse | 7159 |
| Distinct | 7110 |
| SingleOrDefault | 6956 |
| Max | 6805 |
| SequenceEqual | 6487 |
| OrderByDescending | 5987 |
| Empty | 5802 |
| GroupBy | 4897 |
| Aggregate | 4584 |
| ElementAt | 4277 |
| Min | 4232 |
| Except | 3568 |
| Union | 3365 |
| LastOrDefault | 2757 |
| AsEnumerable | 2655 |
| Repeat | 2605 |
| Intersect | 1842 |
| ThenBy | 1745 |
| Zip | 1310 |
| Average | 1117 |
| TakeWhile | 867 |
| DefaultIfEmpty | 704 |
| ToHashSet | 655 |
| ThenByDescending | 637 |
| ToLookup | 607 |
| ElementAtOrDefault | 573 |
| SkipWhile | 559 |
| Cast | 456 |
| Prepend | 408 |
| LongCount | 245 |
| GroupJoin | 138 |
| OfType | 132 |
| SkipLast | 113 |
| TakeLast | 105 |