docs: add related guides cross-references across Base Account documentation

docs/base-account/guides/accept-payments.mdx

@@ -319,4 +319,14 @@ If you intend on using the BasePayButton, please follow the [Brand Guidelines](/
 2. Pass <code>testnet: true</code> in your <code>pay()</code> and <code>getPaymentStatus()</code> calls.  
 3. Use <a href="https://sepolia.basescan.org" target="_blank">Sepolia BaseScan</a> to watch the transaction.
 
-
+ ## Related guides 
+
+After implementing payments, you may also want to: 
+
+- [Sponsor gas fees with Paymasters](/base-account/guides/paymasters) 
+
+- [Use Spend Permissions](/base-account/guides/spend-permissions) 
+
+- [Create subscriptions](/base-account/reference/account-sdk/subscriptions) 
+
+- [Integrate with Privy](/base-account/framework-integrations/privy/setup)

docs/base-account/improve-ux/sponsor-gas/paymasters.mdx

@@ -299,3 +299,13 @@ the [Coinbase Developer Platform documentation](https://docs.cdp.coinbase.com/pa
 
   </Step>
 </Steps>
+
+## Related guides 
+
+After configuring Paymasters, you may also want to: 
+
+- [Accept payments](/base-account/guides/accept-payments) 
+
+- [Batch transactions](/base-account/guides/batch-transactions) 
+
+- [Configure account permissions](/base-account/guides/spend-permissions)