All the tech mods you listed, TE, MFR, Engin. Toolbox, Big reactors, Mekanism, Atomic science etc are all in this pack plus many more, so don't worry they will all be there, look at the list of mods for Yogscast Complete pack on atlauncher website. As Draze mentioned the list of mods it contains is amazing and combination is made so you can really have a lot of fun (monster on the other hand becomes dull very fast)
As for magic mods, I completely agree on thaumcraft, I did everything in that mod and it becomes a bit plain and boring.. (This pack gives us new thaumcraft additional mods like forbidden magic..)
Witchery is not all about curses (and you can cure those or protect yourself), it's about much much more. From terraforming rituals, changing day and night, controlling rain, many new mobs, 5 bosses to slay, each very different and interesting.
You can raise a volcano, make an ice dome, change biome types, make lands more fertile or less if you want, grow a magical forest, summon demons, make a poison frog rain, make magical shield domes to keep you safe..
Have owls, cats or frogs as your familiars and share soul with them. Use owls to deliver items or throw potions on other players.
You can infuse yourself with spirits to gain special powers.. Recruit coven witches and form you coven so you can call them to fight with you or summon them to help you do a ritual or male it more powerful.. You can visit the nightmare or spirit world and even if you want to build a portal and manifest yourself as a ghost in the Overworld to haunt others..
Sign contracts with imps or demons, make a wand to cast many spells like to disarm enemies, create water/fire, confuse mobs..
You can even summon death (very hard to do) and if you beat him few times and get all of deaths armor u can become death itself and do some amazing things..
Also theres a big list of potions and brews you can make some very useful like substitution to change blocks like dirt sand stone to something else.. Then ones that make opponents blind, put them to sleep or engulf them in webs.. Many plants you can set with different abilities (there are even triffids you can grow as your bodyguards..)
You can also do things like ride a broom, summon banshies or poltergeists and bind them into a stone or item..
This is just a small part of this very complex mod, I promise anyone who likes magical mods will love witchery..
Also mod creator is a very nice guy that will respond to your questions and even look through crash logs if you have a problem..
There is even a crystal ball that you can use to read yours or other players future (and riddles it gives you do really happen in game! Its very fun
)
As you can tell I love that mod thats why I wrote a bit more about it..
Theres also ars magicka 2, Bloodmagic, Totems and some more magical mods..