Golf League Tracker offers a number of tools for your one off tournaments and outings which don't require a subscription. Remember, Golf League Tracker is a full fledged system for keeping track of many of these formats below, including skins and Stableford scoring.
The 2020 World Handicap System has changed their method of calculating a player's handicap index. Use this calculator to calculate your Handicap Index, and compare it to the old USGA Method.
With the advent of the 2020 World Handicap System, the method for calculating the player's course handicap, now called the "Playing Handicap" has changed. Use this calculator to quickly calculate each player's Playing Handicap from their offical USGA Index.
If you'd rather figure out your handicap in a spreadsheet, you can use the handicap calculator spreadhseet here.
This online interactive calculator will give you effective playing distance for wind and temperature adjustments. Just enter a baseline temperature, wind speed, and direction and it will determine how far the shot is actually playing.
This excel sheet calculates yardage adjustments for shots from 50 - 250 in 5 yard increments for different wind speeds and directions.
If you're running an outing or one time tournament, you can figure out skins automatically for gross and net scores. Just enter the players, course info, scores, handicaps (if doing net skins) and pot amount and the rest is calculated automatically.
An alternate skins worksheet, this is the game my group plays. Pay out for skins with different amounts if you win with a par, birdie, or eagle skin (typically 1, 2, or $3 for each). Also includes Closest to the Pin computations (we play $2 each).
5-3-1 is a 3-player game in which each hole is worth 9 points. The player with the lowest score (net or gross, depending on the format you're playing) is awarded 5 points, the middle score is 3 points, and the highest score is 1 point. Points are split if there's a tie: Two lowest scores tie then each player gets 4 points, and the high player gets 1 point. If the two highest scores tie then each of those players win 2 points each, and the low player wins 5 point. Finally, if all 3 players tie, then each player receives 3 points.
For an 18-hole round there's a total of 162 points available. Typically the game is played for money for a certain amount per point. For a low money game (< $10) make each point worth $0.25.
The Callaway scoring system is great for single round tournaments when you don't have handicaps for your players. Handicaps are determined based on the scores the player shoots that day, and a number of "worst holes" are dropped from the total. This kind of system rewards the player who is the most consistent. More info can be found online, but here a good source of information.
Stableford allows you to award points for the score a player made relative to par. This worksheet is great for those one-off touraments to quickly and automatically determine totals.