If you are Core 1-2, go away...
I'm kidding. But I'm not making a guide for those two levels because it's too simple to make a guide on

Okay, this will probably be a long post but hopefully it'll be informative. A few notes before we get started:
- These bases are just what I think will work. I will go through pros and cons
- You can copy these designs, modify them, use them as inspirations or whatever
- My nodes will obviously be higher level but I'll try to make sure I don't use any extra nodes for each core level
- I will make both farming and rep pushing bases
- Feel free to comment down below if you want to add something to this list
- I may edit this for higher level cores when I have time
Things to look out for in good networks
Feel free to add more things in the comments
- Good positioning of netConnections
- Good positioning of sentries
- Good positioning of turrets
- Good positioning of black ICE
- Good positioning of code gates
- Good positioning of scanners
- Using Choke points
- Using low and high firewalls to route damage
- Using node connections and program slot knowledge to its maximum potential
Deleting nodes
Sometimes you may not want a node but can't seem to delete it. Maybe you want to replace a mine with a defence node or you want to get rid of a netConnection. What you have to do is put the unwanted node at the end of a network like this and a X will pop up.

The game will not allow you get rid of a node if it is connecting other parts of the network as you cannot tear the network apart like this sentry here:

See how there is no 'X'?
Important note: You DO NOT need a 3rd netConnection at core 3-5. You can delete this as it is just an extra node the attacker can start attacking from. Give the attacker only 2 netConnections to limit their ability to attack by using the method above to delete your netConnection.
You only need to get the 3rd netConnection when you areupgrading to Core 6. Otherwise, delete it.
Okay, now with that out of the way, lets move onto the designs
Note: The nodes listed in the designs aren't set standards or the "meta". They are just what I think works best for me. I just don't want to go through every network combination

Core 3
Max nodes: 13
Business nodes used (4): 1x server farm, 1x database, 1x b-coin mine, 1x b-coin mixer
Security nodes used (5): 2x sentry, 2x turret, 1x black ICE
Hacking nodes used (3): 1x compiler, 1x evolver, 1x library
Total nodes: 12 + core = 13
C3 Farm

Advantages
- Has 3 choke points - Evolver, b-coin mine and server farm
- Sentries pass on their antivirus immediately to the defence nodes which speeds up antivirus spread
- Resources very far back
- Having just one black ICE holding a choke point isn't effective. But then again you have very few nodes to play with
C3 Rep

Advantages
- Has 3 choke points - Evolver, b-coin mine and server farm
- Sentries pass on their antivirus immediately to the defence nodes which speeds up antivirus spread
- Core tucked away nicely with the b-coin mixer
- Again, Having just one black ICE holding a choke point isn't effective.
Core 4
Max nodes: 16
Business nodes used (5): 1x server farm, 1x database, 2x b-coin mine, 1x b-coin mixer
Security nodes used (7): 2x sentry, 2x turret, 1x black ICE, 1x code gate, 1x scanner
Hacking nodes used (3): 1x compiler, 1x evolver, 1x library
Total nodes: 15 + core = 16
C4 Farm all in defence style

Advantages
- Scanner is very heavily guarded. This is a really good choke point as scanners have low firewall and only have 3 attacking slots while still having 4 node connections
- Another choke towards the back with the database
- Antivirus spreads quickly
- Once the attacker gets past the scanner, its pretty much GG
Closer look at scanner choke

C4 Farm spread out

Advantages
- Even spread defences through out the base
- Looks less crumpled compared to the base before
- Antivirus spreads quickly
- Weaker choke points
Scanner range

This is important for defending against stealth. The scanner will activate immediately when the attacker starts from the closest netConnection. I will probably make a scanner/stealth defence guide some other time in more detail. Sorry!
EDIT: I did a section on stealth here
For now, just make sure your scanner is 3 nodes away from the closes netConnection
C4 Rep

Advantages
- Even spread defences through out the base
- Antivirus spreads quickly
- Core tucked away nicely
- Again, weaker choke points compared to the "all in" strategy
C4 Rep rework

Made another one without the double code gate mistake
Advantages
- Two choke points. One on scanner, one on evolver
- Low firewall b-coin mine is difficult to get to the tanky core
- Core tucked away nicely
- Scanner range is good
- Split resource branch and core branch
- Evolver choke point is a bit weak.
Core 5
Max nodes: 19
Business nodes used (5): 1x server farm, 1x database, 2x b-coin mine, 1x b-coin mixer
Security nodes used (9): 2x sentry, 3x turret, 1x black ICE, 2x code gate, 1x scanner
Hacking nodes used (4): 1x compiler, 1x evolver, 2x library
Total nodes: 18 + core = 19
C5 Farm

Advantages
- All in scanner choke point
- Scanner 3 nodes away from nearest netConnection
- Antivirus spreads quickly to the defence nodes
- Resources split apart making the attacker have to go to all of the to get all the loot
- Looks pretty ugly, I think I could do better if I had more time
- Evolver could be used better
Note: The reason I use double code gate like that is because I want to protect the scanner from wraths. If they want to wrath my scanner, they must get through the code gates first
C5 Rep

Advantages
- Fixed the evolver problem, now it has become a choke point
- All in scanner choke point
- Scanner 3 nodes away from nearest netConnection
- Antivirus spreads quickly to the defence nodes
- Resources split apart making the attacker have to go to all of the to get all the loot
- Top sentry doesn't really do much other than activate all the defence nodes. Could be more useful I guess
- Compiler in a really awkward spot
EDIT: Added C5 Farm rework
C5 Farm rework

Inspired by Zepto's "Scorpion"
Advantages
- Looks a lot cleaner than the first two bases
- Has scanner choke point
- Adds another strong choke point at the back on the database. This can be switched out for a mixer
- Sentries in much more secure and useful positions
- Resources aren't as far back as I want them. Furthest node is only 8 (out of a possible 9) nodes away from nearest netConnection. This just means there is room for improvement
- Resource "vault" is not perfect. Im sure there are other "resource vault" designs that are better
Close up of scanner choke point

Conclusion
Well that was quite fun to make XD I hope you learnt something from this post. If you are more experienced than me and spot something wrong, let me know in the comments or PM me and I'll try fix it ASAP.
Took me well over two hours to make this post. Hope you like it! Happy building

EDIT: Photobucket went down, so most my images were lost. Replaced them with Imgur