Broken Link Checker - you can disable that and just run in manually every now and then. It used to use a lot of resources on my server. Alternatively, I think it lets you change the times it runs, so you can check the settings and see if you can make it once per week instead of every 15 minutes or whatever it's default is.
Simple Trackback Validation - I'm not familiar with this one but something similar to that I had once, which really consumed a lot of server resources, so I'd check this one and see how often it runs.
WordPress Database Backup - how often have you set it to run, check that.
Tweet old post - how often does this run? check that.
Twitter Goodies - not sure what this is but if it tweets automatically to twitter, then it also uses wp-cron, so check how often it is doing it.
WP Missed Schedule - dont know what this is, but it sounds like one that would use a cron job too.
WP Security Scan - if this scans automatically at set intervals, then its also going to be using wp-cron.
Here's a post that I just finished reading that might help:
I'm also researching all the cron control type of plugins right now, and testing them all out on my site, so will update when I work out which one (or two) I think is the best, but yeah there was a lot of old plugins but I've found a few new ones too that I'm testing right now.