Which PHP extensions are needed to run a fully operational Wordpress site?

The below list of PHP extensions (for v5.5, in case it differs by version) are available to me in cPanel. Which of them do I need to enable to run a fully functional Wordpress website?

So far, I know I need to enable mysqli (or an equivalent... but it should be better than mysql which is obsolete, and probably better than pdo_mysql which I think is PEAR from memory)

I also need GD otherwise image editing from the Media Library won't work.

Background:
I was told I should update my hosting account from the default PHP version of 5.4 to 5.5. When I did so I discovered my Wordpress site could no longer connect to the database because there was no package for it to use. Adding mysqli fixed that, but I don't know what else I need.

apcu             hidef             mongodb             pspell             translit       
apm             htscanner             msgpack             quickhash             uploadprogress       
ares             http             mssql             radius             uri_template       
bcmath             igbinary             mysql             raphf             uuid       
big_int             imagick             mysqli             rar             wddx       
bitset             imap             ncurses             recode             weakref       
bz2_filter             inotify             oauth             redis             xcache_3       
dba             intl             oci8             rsync             xdebug       
dbase             ioncube_loader             odbc             snmp             xmlreader       
dbx             jsmin             opcache             soap             xmlrpc       
dom             json             pdf             sockets             xmlwriter       
doublemetaphone             ldap             pdo             spl_types             xrange       
eio             libevent             pdo_dblib             ssh2             xsl       
enchant             libsodium             pdo_mysql             stats             yaf       
ffmpeg             lzf             pdo_odbc             stem             yaml       
fileinfo             magickwand             pdo_pgsql             stomp             yaz       
gd             mailparse             pdo_sqlite             sysvmsg             zend_guard_loader       
gender             mbstring             pgsql             sysvsem             zip       
geoip             mcrypt             phalcon             sysvshm                   
gmagick             memcache             phar             tidy                   
gnupg             memcached             posix             timezonedb                   
haru             mongo             propro             trader