Bitcoin Core policy limits (src/policy/policy.h):

Standard script types (Bitcoin Core default policy):
  - P2PK
  - P2PKH
  - P2SH
  - P2MS (bare multisig, up to 3 keys)
  - P2WPKH
  - P2WSH
  - P2TR
  - OP_RETURN (with data ≤ 83 bytes)

Non-standard (will not relay by default):
  - Any script not matching above patterns
  - Bare multisig > 1-of-3
  - Scripts with non-push opcodes in scriptSig
  - Scripts exceeding size limits
  - Scripts with OP_RETURN and > 83 bytes of data

1. Transaction is broadcast to the network

2. Most nodes (running default policy) reject it at the mempool level

3. The transaction is NOT relayed to other peers

4. The transaction does NOT appear in most mempools

BUT:

5. A miner can still include the transaction directly in a block

6. Once included in a valid block, all nodes ACCEPT it (consensus valid)

7. The UTXO is created and is spendable in future transactions

This is the crucial distinction:
  - Policy: enforced by relay nodes → affects mempool propagation
  - Consensus: enforced by all nodes → affects block validity

Option 1: Direct miner submission
  - Contact mining pool operator directly
  - ViaBTC, Luxor, and others accept direct submissions
  - F2Pool "transaction accelerator" for stuck transactions

Option 2: Mining your own block
  - Requires hashrate, practical only for large operations

Option 3: Custom relay paths
  - Some services maintain non-standard relay networks
  - Bisq's trade protocol uses timelock scripts that were historically non-standard

Option 4: Bitcoin Core with -acceptnonstdtxn flag
  - Start node with: bitcoind -acceptnonstdtxn=1
  - The node will relay and mine non-standard transactions
  - Useful for testing on regtest/testnet

# Bitcoin Core policy limits (src/policy/policy.h):
MAX_STANDARD_TX_WEIGHT = 400000          # 400,000 WU
MAX_P2SH_SIGOPS = 15                     # Max sigops in P2SH redeemScript
MAX_STANDARD_P2WSH_SCRIPT_SIZE = 3600   # witnessScript max 3600 bytes
MAX_STANDARD_P2WSH_STACK_ITEM_SIZE = 80 # Each witness item ≤ 80 bytes
MAX_STANDARD_P2WSH_STACK_ITEMS = 100    # Max 100 witness items
MAX_OP_RETURN_RELAY = 83                 # OP_RETURN data bytes