If you find yourself overwhelmed, I would recommend the following that will give you a lot of tools to work with. I think all of these were mentioned by Jarren, who also kindly provided links to things.
Universal Chat Menu
I have the global macros I am currently using for the Pathfinder by Roll20 sheet near the top of (what is currently) the last page of the thread where you find this script. If you learn how to set up this script from the examples given, you can adapt this script to any sheet and use it to generate lists of abilities to trigger from chat. With the Roll20 pathfinder sheet, I find that I can use the same menu for skills between players and npcs, but I have a specific npc menu for everything else. It will show me pretty much anything I might need and allows me to trigger spells, attack rolls, saves, displays the various ACs, and shows notes on various defenses all with one token action. Basically one token action will do that for any npc I have out on the map. It is so much easier running a combat or skill heavy scenario with that script since I very rarely need to open the actual character sheets anymore (basically, I only need to do that in the event of the players getting loot/gifts). Also, players with animal companions or familiars can use the npc menu as well to quickly access info/rolls they may need.
TokenMod
In pathfinder, you will be messing with lighting/vision a lot. There are also a lot of conditions that you might want to indicate with token markers. TokenMod makes all of that easy. Set up the options you need in a Chat Menu, possibly on a Macro Character, which are ideas out of the Stupid Roll20 Tricks thread mentioned by Jarren (the first post is an index).
ChatSetAttr
I really haven't used this script enough, but I can tell you one thing I use it for in Pathfinder. Got a player with augmented summons and another without? Don't want to clutter your journal with augmented/normal versions of the summons? Just use the normal and use ChatSetAttr to alter some of the npc attributes for the higher fortitude saves, str, and con with a ChatSetAttr command. You can have another command to set things back.
You can also do this with notes in the attacks, but there are already notes for reminding me of the possible affects of alignment oriented templates, so I generally change the sheet attributes back and forth with ChatSetAttr. I actually use this in combination with TokenMod so that the HP of augmented summon tokens gets raised also. So that I know how much to raise it, I have a macro that whispers me the hit dice formula.
Door Knocker
I haven't used all of the features of this. The ability to set a color for doors and just be able to toggle doors open/closed by moving a token around on the GM layer and click a token action has been incredibly useful. I haven't really paid attention to all the other stuff it can do, since that is all I need.
Group Initiative
Got groups of npcs that need initiative rolled? Want to display tie breaker stats as part of your roll? Want initiative to automatically sort when you roll? Use this script to make all that simple. You just have to configure it for the sheet/stats you use.
Welcome Package
If you are starting a new game or run one shots where you aren't using pregenerated characters, this script will assign anyone that logs in for the first time a character sheet. It also creates a macro that you can make visible to players that will generate another sheet for those that need to also set up a mount, companion, familiar, or just a sheet to track bag of holding or handy haversack inventory. No need for the GM to be logged in to create/assign the sheet. Obviously you might not want to enable the macro for everyone for a bunch of strangers, but if you have a batch of known trusted players, I have found it really useful.
Compared to others, I am fairly conservative in the number of scripts I use. It really doesn't take very many to have a serious impact on how you run games. You might consider starting small. Try just a few of them and get a little time in using them before adding more. Or not. The convenience can be addicting.