Ethereum is easier than all of these
http://www.theseus.fi/bitstream/handle/10024/123896/Sikorski_Timothy.pdf?sequence=1
Bitcoin cloning guide
https://bitcointalk.org/index.php?topic=1019508.0
Another guide
https://bitcointalk.org/index.php?topic=1030365.0
A thread where someone has a problem making a coin
https://bitcointalk.org/index.php?topic=871564.0
Another guide
https://bitcointalk.org/index.php?topic=420896.0
Questions and answers about genesis block
http://stackoverflow.com/questions/20772606/how-to-create-a-genesis-block-of-my-altercoin
https://bitcoin.stackexchange.com/questions/21303/how-can-i-create-a-new-genesis-block
https://bitcointalk.org/index.php?topic=651695.0
https://bitcointalk.org/index.php?topic=1011041.0
Learncoin (the coin in the video guides) on Berkley's website
https://www.ocf.berkeley.edu/~baisang/LearnCoin.pdf
Practicecoin
http://practicecoin.com/wp-content/uploads/2017/04/Cloning-Bitcoin-0.8.99.pdf
Another guide
https://altcoinsfoundation.com/forum/developers/56-how-to-create-your-own-cryptocurrency-altcoin-1-dev
More genesis block info
https://www.quora.com/I-want-to-create-a-new-altcoin-How-do-I-generate-the-Genesis-Block
Bitcoin protocol
https://pdfs.semanticscholar.org/e85a/a20a544f521b9ac529027fce3cbd28dc637b.pdf
Another guide
http://www.0speed.net/2016/10/24/how-to-make-an-altcoin/
Here is the Practice coin thread on Bitcointalk
https://bitcointalk.org/index.php?topic=1850047.0
Another guide
https://pastebin.com/iL9DeTTS
https://bitcointalk.org/index.php?topic=1151674.0
Discussion about forking ETH
https://ethereum.stackexchange.com/questions/2014/how-to-fork-my-own-version-of-eth
According to at least this person, cloning Ethereum is extremely easy and he says there are only 2 steps
https://bitcointalk.org/index.php?topic=1361504.msg13857758#msg13857758
Programmer's Guide to Ethereum and Serpent
https://mc2-umd.github.io/ethereumlab/docs/serpent_tutorial.pdf
A Treatise on Altcoins
https://download.wpsoftware.net/bitcoin/alts.pdf
Gitian Builder
https://github.com/devrandom/gitian-builder
Making a mining portal
https://github.com/UNOMP/unified-node-open-mining-portal
Building wallets
https://cryptocointalk.com/topic/13204-how-to-build-a-windows-qt-wallet-for-any-coin-yourself-from-source-code-step-by-step-instructions/
https://bitcointalk.org/index.php?topic=586844.0
https://bitcointalk.org/index.php?topic=498746.0
PoS Coin making Guide
https://steemit.com/altcoins/@complexring/how-to-build-proof-of-stake-altcoins-and-stake-coins-on-a-remote-ubuntu-server
This coin claims to be an in wallet coin generator
https://bitcointalk.org/index.php?topic=1287935.0
Video guide
https://bitcointalk.org/index.php?topic=1278734.0
Building headless Bitcoin on Windows
https://bitcointalk.org/index.php?topic=149479.0
Here is a written guide
https://bitcointalk.org/index.php?topic=225690.0
Here is a thread where someone asked a question, and linked a guide
https://bitcointalk.org/index.php?topic=615244.0
Here is how to create a Cryptonote
https://cryptonotestarter.org/
Free & paid coin creation site
https://www.walletbuilders.com/
http://coloredcoins.org/
Coin generator
http://build-a-co.in/
These aren't really coins, but are contracts that are kind of like coins. Kind of like shares of a company that are represented by coins/tokens. They can be used various ways, but are usually advertised as if they are Cryptocurrency, but are not really.
https://www.ethereum.org/token
https://bitshares.openledger.info/account/(your Open Ledger username)/assets/
Another collection of guides (good ranked list)
https://bitcointalk.org/index.php?topic=1801477.0
Compile guide for Windows on Linux
https://bitcointalk.org/index.php?topic=1080289.0
A few cloning guides
https://forum.gethashing.com/t/how-to-clone-a-coin-links-and-resources/3833
http://dillingers.com/blog/2015/04/18/how-to-make-an-altcoin/
https://cryptocointalk.com/topic/3140-shakezulas-scrypt-and-sha256-cryptocurrency-clone-guides/
Not exactly sure what this is, it claims to be an in wallet coin creator, and I assume it is like the ethereum and bitshares assets/contracts, but it may actually be an in wallet coin creator.
https://bitcointalk.org/index.php?topic=1699319.0
Adding premine to coin
http://dillingers.com/blog/2015/04/23/adding-a-premine-to-an-altcoin/
Genesis Blocks
Most of the guides include this information, but I'm adding it just so that there is as much information in this thread as possible
http://stackoverflow.com/questions/20772606/how-to-create-a-genesis-block-of-my-altercoin/22406608#22406608
https://bitcointalk.org/index.php?topic=189350.msg2035449#msg2035449
Genesis block Generator
https://bitcointalk.org/index.php?topic=181981.0
Some developer links
https://bitcointalk.org/index.php?topic=763471.msg8604040#msg8604040
Another guide
https://bitcointalk.org/index.php?topic=193025.0
Another guide
https://bitcointalk.org/index.php?topic=217636.0
How to Clone PeerCoin
https://talk.peercoin.net/t/creating-a-genesis-block/4337